Stealthy jet skis: highly unrealistic, because moving a jet ski creates waves - how you stealth water waves? Yeah.
Smarter AI: we all want it, but it's hella hard to code, man. This game has better AI than most others, too - at least no blatant holes in it. Me thinks.
Minmaxing stats: it's the staple of the genre, man. I mean, being able to minmax stats with very tolerable (not dramatic) penalties for doing so. Lots of folks who play this sort of games really want it. Not likely to change.
Weapon balances: impossible to do, given amount and effectiveness of stats, skills and perks. Same weapon will do vastly different depending on character build. You nerf the weapon for some builds where it's "OP" - then this same nerfed weapon becomes way too weak for most other builds. This is why it's simply impossible to do.
Picking your maximum hit chance: actually this is doable to an extent. It's 95% cap for gunfire, but 90% for grenades and other AoE attacks, yet it's 100% for most Psi abilities. So you can make a build which does damage with one or more of these damage types based on your preferred max hit chance. Also, whenever you'd need anything lower than these chances - can always reduce your hit chance by intentionally suffering one or more penalties to hit chance (of which, there're quite a few). And naturally, 105% chance is the same as 100%, in practice.
Many builds having trouble killing hardened foes: simply not true. You just need to learn relevant possibilities. For example, any gun-based builds all have access to large amounts of W2C ammo, which negates much of armor. Certain melee features also do it, iirc. Psi builds just couldn't care less about armor, too. As for robots - any build can use EMP traps (at least mark 1 - even with 0 points in Traps skill, by using items with sufficient Traps skill bonuses), and EMP grenades are simply always available, on top. You can buy 'em, and you can craft 'em if you have corresponding crafting skills, too. And then there's a certain device in the game which really messes robots up, if you'd still need more oompth against robots.
