CoH's system was a little wonky, but I loved it.
I kinda agree with Tenzhi that outright losing benefits from your enhancements as you levelled was dumb. The way generic IOs functioned should've been how TOs/DOs/SOs worked.
However, this was, and is, my sole complaint with the system. I enjoyed IOs when they were released, and I crafted the hell out of them when they were still new and market prices were still cheap (few people had hundreds of millions of inf). The ability to use my enhancements without fear of them suddenly becoming useless was a vast, vast improvement over having to struggle with enhancement obsolescence, to the point where I eventually started selling any standard enhancements I picked up to NPCs in order to fund the purchase of more invention salvage.
Even with nothing but generic IOs, I was able to feel appropriately strong, was never really hard up for money (though I was never fantastically wealthy either), and felt that I was contributing to my team unless teamed with people running tricked out IO-set builds, or who were loaded up with things like Hami-Os. Further, my enhancements never bothered my appearance, and within the limits of the costume parts available to me, I could always look JUST the way I wanted.
That was the beautiful thing about CoH's gear system.
So far, few games have ever let me have that level of customization. Sure, there are games that let you separate a piece of gear from its stat bonuses, or allow you to graft the looks of one piece of equipment onto the stats of another, but it always feels like a poor substitute for the sheer versatility and flexibility of CoH's costume creation system. Thus far, only Champions Online even comes close (and to be honest, it's actually a bit better in some ways - easier to create asymmetrical characters, for instance, even if it is more cartoony.)