Anyone else think that the Deathwatch as the overall playable Space Marine chapter would have been better? Having 4 Space Marine chapters running around on the same planet seems a bit odd. I understand that everyone wants to be from whichever chapter they feel loyal to and it would still work. Having all players be a part of the Deathwatch while still being allowed to have your home chapter would also help the Black Templars be included. The players choice of which chapter they choose would give the player a different racial bonus.

The same can be applied to Chaos as well seeing as how the Black Legion pull troops from every cult and warband. This way, a player can align themselves with whatever Chaos god they choose from the beginning, granting a bonus.

I just don't get why there are so many SM/CSM chapters on this one planet.

Because they want to play the other subfactions, nothing more to add to that really as an explanation.
Your way of doing things would drive thousands away, especially for Chaos cause the current legions are truly different from one another (well aside from the BL, which is basically the jack of all trades).

The reason why we are allowed to have 5 (and more to come later) chapters/legions/klans/craftworlds is the same reason why millions upon millions of marines will die to the point where every chapter would be extinct, why people will magically be popping into existence upon spawning, why people shot in the head by what could pass off as a small missile will not have their heads implode etc.

This is a game first and foremost, and to actually be a good game it steps over certain things to be both interesting and playable.

Deathwatch never deploys on big numbers, they use squads of elite troops, it will be funny to see more deathwatch marines than orks

Badab Uprising? Black Crusades? Damocles Gulf? Medusa V? Armageddon?

I mean I think it's gonna be an aesthetic nightmare having random blobs of different chapters running around, but them all being in the same place is in no way unprecedented in the lore.

Hell, they made an entire expansion for the tabletop based around it

Now where's my 30 Deathstrike Missile Launchers...

Seriously though, if you find four nominally allied chapters more problematic than thousand upon thousand of marines from a very small order that is well known for operating only in small numbers and that admittedly could faceroll at least through the Orkz and Eldar, I question your priorities.

Thanks guys! I'm just over here trippin out. Lore wise, yes it does make sense to have a lot of different factions on the same planet. I think what worries me the most is the background fluff for the system of planets and the involvement of every faction.

I need more stories to read.

Think of it like this, it often goes like, the more interest from other factions=more interest from even more faction, and the orks just come to fight. Im sure this war is big enough to warrent 5 sub factions of every race.

They've made up a reason this planet is important enough that the Imperium doesn't just blow it up and be done with it, so it'll be important enough for coalition forces to fight for it. They of course haven't revealed that reason yet, but if you aren't aware they have already brought over Reynolds and McNeil from BL to formulate a backstory that should be more than adequate for an explanation.

Also I never had considered having multiple sub-factions to be a problem.

It hurts my head trying to think why 4 first founding legions would all come to the same planet. Either the Ultramarines made a big journey, or the other 3 all made a big journey considering they are pretty much opposite sides of the galaxy and all.