The lack of usability in the auction house is easily the largest contributing factor in the frustration surrounding crew skills. If people cannot buy & sell materials and crafted items effectively, crew skills will continue to be underwhelming.
"Just wait for the economy to get off the ground." How many times have you seen that statement in these forums? If nobody can/wants to use the GTN, the in-game economy will NEVER get off the ground.
No, the ease of gaining commendations along with the commendation vendors stocking a large (if not complete) range of blue (or better) equivelent gear is the largest contributing factor in the frustration surrounding crew skills, as that makes it so vendor bought stuff is as good/better than crafted. I would have argued commendations should solely be obtainable through raids or flashpoint dailies. That would go a ways towards improving crew skills right there..
I will say the 2 window limit is *also* extremely frustrating, especially combined with the fact that opening the GTN also (needlessly) opens your inventory.
All that said, from an infrastructure point of view, how the GTN works makes tons of sense. (other than the inability to filter by slot) The string search filter is an intensive process. I'd be willing to bet that aspect of the search is 100% clientside. The rest of the filters I'd suspect are entirely server side. So of course they want to narrow down the results before it sends the data clientside and does the hard/local one.