And seeing that it is now free, I see a lot more new players coming to TOR than WoW over the coming months, maybe even years.
I completely agree with this part. And I really hope it works out for them. F2P has a lot of potential that I feel some players are too keen to dismiss. But as for the rest of your post, there's two things you may have missed:
1) "For a new player, TOR is by far the more enjoyable experience to get to endgame." - Like you said, Cataclysm overhauled 1-60 and modernized it. It's an incredibly fun and easy-going leveling experience. For new players, experiencing the game for the first time, I'm sure WoW is just as much fun as SWTOR. I agree BC, and even Northrend to an extent, need overhauling as well, but for a player to get that far they will usually see things through to 80 where the content picks up again. And MoP's content looks amazing from what I've seen of it.
2) Regarding empty zones - I'm guessing you aren't aware of the zone merge technology Blizzard introduced a few months back. It isn't working in all the zones yet, but certainly is in most of them - especially the starter zones. Players are merged into zones regardless of server (so long as they are the same type of server: PVP, PVE, etc) so that empty areas are rarely an issue these days. It doesn't solve all of the low-pop server issues, but it's a great way of repopulating the zones. I used to meet a lot of players leveling while I was performing Archeology with my main.