One of the biggest barriers to this game is, in my opinion, the skill system. Points are not easily or quickly acquired and much of the weapons and suits don't show any real promise until at least the 3rd skill level. I understand not having an easily accessed skill respec, as it would mean players could change their role on the fly (and therefore give high-SP players an advantage in ALL battles). However, a scaling skill respec wouldn't be amiss, especially for new players.
Many of the weapons in the game don't have comparable fellows in other FPS multiplayer games. I'd like to try out things like the scrambler rifle, or the laser rifle, but won't because I'd be locked into that or simply have a good chunk of points burned into something I'll never use if I don't like the weapon class. Secondarily, every time hotfixes and complete overhauls occur, the individual changes alone can make or break whatever class you're in.
I've played maybe twice since the massive May 6th update. I absolutely hate the changes to the class I used prior to the update, and feel my points have been largely wasted. I have requested a respec, of course, but I have no doubt that this will be a continual problem as the game evolves. And I am one of the players who've put actual money into the game. I'd have put more into it this weekend, except I have very strong doubts I'll want to play this for much longer (and my #1 problem is the lack of respec).
Lastly, for every person complaining about various weapons being OP (and we have ALL done it), a respec offers a simple solution. If a weapon is OP and being heavily used, you simply change your skills to compensate for it. It allows for player-based responses to 'OP' weapons rather than needing CCCP to tweak things on a constant basis. (Plus, I suspect most people claiming OP weapons could skill into them and see for themselves that they aren't, putting down a big chunk of complaints.)
My suggestion: a respec system that is extremely expensive (ISK-wise) after the first use. And every time you use it, doubles or more. Eventually, you'd never be able to get enough ISK to afford even a single respec.
A postscript: I searched and didn't find a topic for this, so if it exists, please move my post there. I never seem to find what I'm looking for with the search system.