@Vita no one can say for certain what a good server would be to play on as alliance, mainly because on server population information is available as blizzard blocked census from working.
Generally the higher populated realms are the PVP realms and then you are looking at the ones that have been open since launch (excuse these spellings), Shazzhrah, Gehennas, Gollemag. Gehennas specifically has a very well known and populous guild on the alliance side in the form of APES, a hardcore PVP focused guild.
The server that some of these guys here are on is Noggenfogger, I am also there. The horde definitely outnumber the Alliance, I would guess 2:1, but theres always enough alliance about to keep groups going and progress smooth. As a hunter you would do just fine here.
Small changes, but the main one is the itemisation is from patch 1.12, so actually things are easier due to better gearing and content the same as before. The grind is still the same, but the knowledge and information that's out there make it much easier to deal with.
I just dinged 60 on my warrior (worst class to level solo) and levelled pretty much solo for all my world questing, did it in 7days 2 hours played. Compared to my first character in vanilla which was something like 14/15 days.
Also meant to add that there are multiple MC and Ony pick up groups running each week with pretty good success, most of them clear.