Let me stop you right there and tell you flat out that you should never present your personal opinion as anything other than the minority viewpoint it is. A good balance system even (in the pvp parts of the) game can (and the success of said games proves that) very well use and utilize invulnerabilities. If you want to disregard that i would suggest taking a very close look at highly successfull and longtime games like wow or dota2 or League of Legends or Destiny 1/2 or Overwatch (all games played by millions) which manage that functionality quiet well and balanced. Or i could name some pve focussed games like warframe or even upcoming PVP games like crowfall which find exactly the right finetuning for it. So please either play better games or tune down your wide generalisations and strong personal opinions to the reality. Having said that pretending this would be unrealistic in 40k (rosarii and forcefields anyone?), overpowered (like psykers?), frustrating (like JPAs?) or anymore gamebreaking (like bolter apothecaries with zombiegrenades?) is just funny. Every other accessment you make is probably your own opinion as polarized as it may be. Allthough you do realise that invulnerability does not have to always come in the form of damage absorbtion? Considering we have already 2 different forms of invulnerabilities you probably overlooked. Jumppack and Cloak. You can't shoot what you can't see or quickly track. It is all a matter of finetuning it, which i suggested by long cooldowns or tweaking it's active time window. The core fact remains unless you change something and give the banshee a niche it will never leave the scorpions shadow and i personally havent heared of banshees with shields. Not to mention that playing around with the banshee base LP will probably never happen. This sets base classes apart from the Veterans / Elites and unless you start to rework all LP costs over all factions i don't see the banshee getting a new 1000 armor trinket for 10 LP. This leaves only 2 possible avenues open. Readjusting what we have, squeezing 20-50 LP out of the screammask? Or option 2 reinvent the special perk for a new role while keeping the rest intact. And option 1 in my opinion is not worth the time or breath cause it will literally change nothing.