I think their position might actually be worse than they let on

Tyranids are actually, comparatively speaking, much easier to stop than most other races. Perhaps not in the battle, but in the war.
Think about it: what happens if you stop an Imperial attack from a neighboring planet? They go back, lick their wounds. In about twenty years they can have rebuilt all the men and material they lost and be right back.

But if you stop a Tyranid attack, they're seriously in deep. Everything they lost through the whole campaign is simply lost forever to the race as a whole. All of their earlier victories getting to that point were completely wasted, and don't help them at all beyond how much it will cost their enemies to rebuild the worlds.

A Tyranid-fallen planet doesn't keep producing soldiers. It won't bury its war heroes and use their memory to wage another glorious battle. It can't send supplies to an exhausted fleet.

Wherever the Tyranids come from, its clear they weren't used to anywhere near the level of organized resistance they're facing, where empires can force them into prolonged slug-fests on world after world after world.

My guess is they just had to face perhaps a quadrant of independent planets. They could use everything, move on, and be stronger for it.

But now they're in over their heads. Their rapid genetic engineering is a desperate struggle to adapt to prey they were completely unprepared for. Look at how many Hive Fleets and their tendrils have been completely stopped in their tracks because they smashed into something they couldn't break.

Without a constant stream of victories, the Tyranids die.

Arkhona is going to be yet another wall they crash against in vain.

Possibly but I'm not seeing any of those limits.

Hive Fleet Kraken might have lost to Iyanden but what was left was still a hive fleet that went on to devour more worlds afterwards. It is still around I believe. In comparison, what does Iyanden have to show? They lost 4/5 of the Craftworlds population but Kraken by the sounds or it is still doing pretty strong.

Then there have been even bigger Hive Fleets like Leviathan ext. There is no sign of exhausted resources for Tyranids. The impression I have as well is that when they hit a planet, it is probably lost to them and they consume it in producing many many more Tyranids.

We all know Eldar have it really hard, and the Imperium of Man is under the gun too, but they haven't felt that gunshot to the heart as the Eldar have. None have felt anything near the magnitude of loss the Eldar have; but it doesn't diminish the fact that humans are in a loosing battle just like us; they just don't realize the scope of things.

All the 'forces of darkness' on these boards and everywhere else love to tell ya how your kind is done and it's just a matter of time before they level the final executing blow against us Eldar and Humans because they have no threat to their numbers, their strength, their empire or their ability to recover. Chaos have the Eye of Terror that is pretty much untouched by their enemies, Tyranids seem to have endless forces that consume everything they touch to produce far more, and Necrons just rebuild themselves into infinity and Orks, well they just grow from nowhere and shabang you have a Waagh in the making.

So for them to lay down the smack talk is easy, because they don't have to back it up nor a weakness they have to learn to survive with. They can just throw numbers to probe enemy weaknesses, where we need rangers to probe and come back alive for the next fight.

Eldar fate all goes towards destruction with the possibility of Ynnead to give us final retribution against Slannesh and all those that have targeted us and once again bring our Empire back, but more improved with our own diety behind us this time.

Comparatively, the rest of Hive Fleet Kraken was just a nuisance that needed mopping up. According to Lexicanum in their article on the Second Tyrannic War, after that battle all that's left of it are "splinter fleets and remnants".

It seems like the significant forces that were left went to that planet Hollohan, where they were destroyed. Afterwards all that seems to be left of any note was what was engaged in the Battle of Duriel, and they only survived because they were caught in a warp storm.

So while its true that with the planets they hit they made many many more Tyranids, ultimately it didn't help the overall Tyranid war effort (beyond the damage it did to everyone else's). Every Tyranid made from those worlds has been slain. (Or is MIA lost in the void somewhere)

Leviathan's scary, but its plans were wrecked at Tarsis Ultra. Instead of having its two main tendrils spread their Shadow in the Warp like a net across fish, now its just one main tendril helping us fighting against an Ork empire. (And it seems that's the other main tendril, since that war is so intense even the Swarmlord himself is fighting in it)

So take heart! Our brethren's sacrifice in Iyanden was not in vain - they dealt the death blow to an entire Hive Fleet. The Orks of Octarius could quite possibly do the same - but breaking themselves in the process. The Tyranids so far have faired disastrously in their predations. If we can hold - as we are holding - they will never threaten another galaxy again.

To be honest Iyanden hold better than entire human systems with SM chapters and IG and PDF detachments.

The Imperium simply doesn't take a long enough view to manage an alliance with the Eldar. They only plan a century or two in advance, if at all. Whatever gifts of foresight they have they misunderstand, squander or burn at the stake. And if they did have any idea what was going on more than ten minutes in advance, they'd know what the Eldar did at Armageddon. So if they were worth the Eldar allying with, they'd not ally with the Eldar (the Eldar are, evidently, the Groucho Marx of the 40k universe). Never mind that there's probably a half-dozen humans in any given quadrant that can recognise the Craftworld/Exodite/Corsair/Commorragh/Harlequin distinctions.

Plus, if it comes to it, the Craftworlds do still have their forbidden reality-destroying superweapons. I think that assessed objectively, the Craftworld Eldar and the Imperium are functionally in an alliance. It's just that the Farseers are in charge, and the Mon-Keigh don't know.

it always bothers me that the nids can even catch up to Iyanden or any other craftworld. other than plot convenience i see no reason why craftworld can't just move away from the path of the nids. or just warp out of the system.
same in the "path of the warrior" books.

Because they're slow? They move via solar sail for a start, and they can't just "warp off" because the Eldar can't use the warp. Their only FTL option is the Webway, and we know that the larger something is, physically, the fewer Webway routes it can use. Presumably Iyanden was making a necessary stop in reality or was en route between webway gates when Kraken caught up to them.

If thats the book I didn't like certain things about but it had awesome sauce Warp Spider Phoenix Lord like guy, then yes, that Craftworld is moving but it can't escape the gravity pull of the Eye of Terror I thought as they were to far into it. Even with their higher tech, a Craftworld is literally the size of a planet, which would also be able to hold far more population than a normal planet would. These things don't turn on dimes or Ramming Speed Mr. Sulu.

Then again who is to say a Tyranid Hive Fleet moves any faster. But for plot reasons they had to turn into the wave to deal with it.

Actually - and I forget this myself most of the time - Eldar do have warp capable vessels, but they don't have the Navigator gene.

They're also far too attractive to anything daemonic and hungry within the warp to make using such vessels anything but a pretty last ditch option, and then only for short jumps. I forget about it because it's just not something they do much of. That's ships; Craftworlds are too damn' huge for that kind of shenanigins. Even if they were able to go into the warp (Altansar being somewhat different in that it didn't jump into warpspace but got sucked into the Eye of Terror) all it would take would be one weak point and you've got yourself a daemonic incursion. There is simply too much risk and too few Eldar to effectively patrol the whole worldship while in transit to make sure nothing gets in. Those are my opinions, anyway

As for what I want for the future of the Eldar race,

"What do I want? Well, that could include all manner of things - peace, prosperity, love, laughter and the leisure in which to enjoy them."

- Motley, in Path of the Archon