Way back when I first started playing and the level cap was 20 and people asked you to link BBs(that's boss beaters, kids) before getting into a Shroud group the +2 tome you received for achieving 1750 favor was actually useful. Now true, tomes actually dropped in quests back then and you could also get them from raids but if you were unlucky with the loot dice that +2 tome was useful. Now, more than a decade later, when it appears tomes have power crept up to +8 we are still being offered +2 tomes that are near useless. Well, 1750 favor is much easier to get now one might say, and they would be right. However, back in the +2 tome era you also lost your tomes when you TR'd (how bout those apples?) and when they did carry over you still had to run OOB 10 times each life to eek out the XP needed to get a 3rd TR. Since pretty much everything has been made easier/streamlined these days doesn't it make sense to at least double the +2 tomes to +4 and increase the 5000 favor +5 tome to +6. This still leaves players appropriately separated from the +8 tomes available for purchase but does modernize and close the ability score gap.
If 1750 favor is still felt to be too low for a +4 tome, swap out the Favored Soul and tome reward so you get Favored Soul at 1750 and a +4 tome at 2500. 2500 requires you to do quite a few quests in a life so you're not exactly giving something away for free in that case. Further, the gloss that was once FVS no longer applies. Many (most?) classes surpass it and being a FVS carries no in-game benefit that it did many years ago.
Updating the +2 tome seems long overdue, as now I'm sure 95% of them end up being turned into 9 purified shards, if the player even bothers to hit the crafting station before TRing.