What I think is:
F2P is A LOT LOT better than endgame wow. It just is. Maybe it's just me. Ppl who play F2P for a long time and they dont have subbed wow sub. Some make their mistake of subbing the F2P, some are clever and make a new account. Every single one I've met like that comes back to F2P after some time.
And now: Getting the caps of the Classic WoW, we have 1/3 of the Level Cap and the Prof Cap. At level 20 we have access to Shadowfang Keep which lets us loot some really really rare gear like SF or MTB (Which also is BiS for some classes!), have access to WSG and AB, Leveling can be done in 1 day.
On level 40: Dungeons like Razorfen Downs, Scholomance and Dire Maul will be probably our best. Swiftness potion will lose it's so imporatant meaning. Levelling will take 2-4 days. Every BiS item will come from Scholo or DM, eventually from a quest - you will not have any cool things like LFH - it will not be anything anyone cares about. AGMs, LFHs... getting items will become standarised. if we have lvl 40 we don't get any new BG. 44s will still have a lot better enchants and will simply have more chance of winning. Everyone who put a lot of time and effort into their F2P char are gonna lose it - and no one likes losing that.