Thoughtful & thoughtless is usually a mismatch. But there are thoughtful guys who are more tolerant and don't require much back in return. If that satisfies them, fine, but I think they're being shortchanged.
One is not over an ex if they talk about them a great deal, make comparisons about them with their new love interest, and of course, if they stay in very close regular contact with them. Some exes do become close non-romantic friends, however, and the distinction is often difficult to make between someone's old friend and being your love rival. It's very situational, but if the ex intrudes on your relationship then it's probably a problem.
Impediments to being open can include tension and lack of confidence. Curing them can improve openness, as can trust in the other person. Therefore, increasing openness often comes naturally over time during a relationship. The opposite evil side of openness is deceit, which should never be practiced.
Enough is enough when you aren't happy any more. If you're not happy and continuing with a relationship, you should analyze your motives. Is it from habit, fear of going single, financial entanglements, reluctance to hurt the other guy, dislike of major life changes, etc?