I'm just not so sure about this. I have a similar thought, but going the other way toward Delta. I've been Plat with CO for 7 years but it just doesn't seem to be moving in the right direction for me these days...
Missed a bunch of upgrades coming down the stretch last year. Last of which was a transcon on 22 Dec, EWR/SFO. Checked in EXACTLY 24 hrs in advance, was #1 on the list the entire time right up to the gate. In the time it took for me to get from the PC to the gate, I went to #2 on the list, all the while the GA was having a very personal conversation with the person who miraculously became #1 on the list (Who's upgrade did end up clearing). Think there was some list jostling going on there

??? To boot, she was downright rude and dismissive about it.
I think I'm just tired of the battlefield UG's. Also saw my upgrade % drop a lot in '04, all the while purchasing better and better fares, checking in well in advance, booking well in advance, etc.
couple that with CO's recent announcement to get more 753's which will undoubtedly be employed on my routes, smaller FC cabins, converting more 757-200's to int'l configurations...It just isn't adding up well from my end right now. Meanwhile DL is flying 764's on my routes with a FC cabin including 30 seats (with power ports in all seats). Even their 738's have power at all seats. Although CO may beat them hands-down in service, I'd rather have a better shot at a mediocre FC than stressing about battlefield upgrades right to the last second...It just isn't worth my trouble these days I think....
Perhaps I'll be sorry next week after I step off DL metal. Oh well, at least I have until about April to test out the theory, after that I'll not be able to retain PE on CO for '06.