They really haven't done anything to improve the Y product other than to add personal IFE, which is something many legacies also have, and provide a better selection of BOB.
The bolded section should have an *:
* on some domestic plane types, but not all, as opposed to VX, which has it on EVERY flight
Product consistency counts. The legacies do not have it when it comes to IFE, and they won't have it for a LOOOONG time.
Also, inseat 110v power in Y, WiFi on ALL flights. I put the odds of legacies having the former fleetwide within the next 10 years at approximately never; WiFi should happen soon, though.
There, VX is one of the worst carriers out there due to the poor design of the coach seats.
That's an opinion.
I've flown lots of single-aisle US domestic coach in the 2+ years since I started flying VX in coach (ordered in approximate order of how many hours I've flown in it): AS, WN, DL (ex-NW and original DL planes), AA, US. I don't find VX coach uncomfortable (and I'm not a small person), and in terms of pitch, VX has identical pitch to AS and WN, and better than AA/DL/US.
In addition, every, I mean EVERY acquaintance of mine who's flown VX has liked it and said they will be flying them again, and I know they aren't all flying in the F cabin (in fact, my 11 year old daughter, if you gave her a choice between AS F and VX Y, would pick VX Y, and she's flown both). Now, mind you, my friends are all mostly casual, occasional flyers, not road warriors/FT mileage hounds, and it's a collection of anecdotes, not empirical data, but this makes me skeptical that your experience is typical. That doesn't make it invalid- it just means Your Mileage Has Varied.