I completely agree regarding XP costs. It is way to easy to raise them with the current skill listing. I become very stingy in my games because of how easy it is to raise skills. But, I also will not allow a character to buy or raise a skill they have not used or attempted to use during play or downtime. For example, if one of my characters tell me during downtime they start training on the holodeck for armed combat, I'll allow them to buy the skill the next game.
Another thing about ICON that drives me nuts is the Renown system. For example, we have a character who has an Aggression of 10. He does something very unaggressive that gives him a Renown "reward" of -3. Now, he has a Aggression of 7, but his Renown has gone up by 3. Anyone come up with a good way of keeping track of this? Or am I just a goober? (don't answer that :-) )
In regards to my system and ICON, either way the systems were built to focus on attributes because that is where you get the dice to roll. I feel the way I use my skill totals are better because it makes a significant difference from someone who has a speciality in Phaser Rifle as oppossed to someone who does not.