Just got my toons to 25 in Alaran language skill and I was ASTONISHED how many very useful (indeed, NECESSARY) spells were locked behind the completion of that work. My boxed set is caster-heavy and I just bought over a 100 spells, many of them providing HUGE boosts for my level 95 toons. It was "nice" that the single-target versions of symbol, skin, haste and crack don't require any minimum Alaran but it's sure nice now to have the group versions and not to have to cast these spells individually on each toon.
Yeah, I did this part of VoA advancement very belatedly. Which made it a lot easier for me since I did all the quests in Lunanyn and the zone was empty most of the time, giving me competition-free access to camps and spawns. I can imagine what a logjam these quests must have been back when VoA first went live.
This expansion appears to have been rather UNpopular and I think a lot of the reason was locking spells (and AA's, and to a great extent, quest armor) behind acquisition of language skills achievable only by doing specific quests. Frankly, I think I should and could have done this a lot earlier but the general negative discussion about VoA in various game-related forums led me to procrastinate tackling these "challenges", as I never like to be "forced" into certain very limited paths for advancement. My loss, ultimately. But I do think it was a major mistake to sell customers an expansion with a 5-level cap increase but locking vital spells behind quests which are rather hard to do without attaining those levels first. In essence this forced players who invested their hard-earned dinero in this expansion to play "crippled" for quite a while until they levelled up and geared up enough to cope with the challenges of the quests needed to unlock the spells and AAs. Yeah, some players will argue that these kill and loot missions weren't all that hard but those players tend to be well-geared raider types. I do remember first tackling a couple of the kill missions at level 90 and they were pretty brutal.
I think locking Rank II spells, and maybe a few exotic spells (nice to have but not class-defining or otherwise essential) behind quests isn't a bad idea. But how they did it in VoA... well IMO they won't ever do this again because very few players are ever going to list this particular expansion among their favorites, I don't think.
And don't get me started on how they locked druid and wizard VoA ports behind ludicrously HIGH Alaran language skill requirements. That's a rant for another weekend when the sun isn't shining and the birds aren't chirping! ;)