I used to max aa every 5 levels or so, and always level to the next multiple of 5 when PLing because it was more efficient. Now with autogrant I mostly do max level, but it really DOES play a big factor, having the aas. If what you're farming is all stuff you can't use til a particular lecel then I'd go to that level, but if you can use it now I'd grind the aas. If you can kill stiff 5 levels above you, then go level. But if you're stuck farming current level then aas for sure will help a lot. There is NO guarantee that 5 levels and the spells discs and fear that go with them will make higher content doable. Higher content is geared to start with previous expansion stuff, so if you can't, then don't push the levels.
When CoV launched, the autogrants from eok made a huge difference in tanking. Because those are 105 and under, there's no reason to worry about aas til 110, as content is tuned to the previous expansion aas and gear. If you can't handle 115 stuff, the levels and gear will help, but the aas can very well make a bigger difference. CoV is tuned for 113-115(as is apparent by quests requiring 113 to get) but ToV is tuned for 110 with Ros aas, and eok is just below that. So, if you can't handle 115 content at 115, it's likely that aas are the problem. There are key aa lines that should be maxed to level every 5 or so that will greatly help, while the rest can wait. At 110 for instance, as a tank, you'd want to max ca/cs, and if the tank is a knight, there are other important lines, but once you do that the remainder can certainly wait. On bard and chanter, lines affecting mez should be maxed. On ranger, zerker, rogue, their respective headshot/assassinate, etc should be maxed every 5, and often I'll do triple attack and weapon affinity as well for example, but most other stuff can just wait. Healers should do healing gift and adept at least as well.
Most aas can wait, but the key lines should be maxed at 110 before going 115. In my experience, the power gains from gear and weapons are negligible without the key aas. Anything below 110 will be fine with autogrant. Key aas are probably only about a thousand, give or take a few hundred depending on class, at 110 with autogrants, and that's less than a weeks work if you focus on them just a couple hours a day(a lot less I'm sure if you afk farm them)
I say all this as someone who was max max way back in RoF, then left until Ros. During Ros I pumped out levels to 110, got almost no autogrants(on tank, alts weren't max to start with) and though I could do some Ros stuff, it was a major struggle and I stuck to work stuff. Ros was tuned for having the enormous power gains from eok aas. I only played about a month before leaving again until this November. I pushed to 115 pretty easy with TAs etc, but Ros now being doable, was not cake still. I tried TBL...that was painful so I went back to Ros again because eok was too low to be worth messing with now. It wasn't until CoV launched and those eok aas magically appeared, that Ros became the cake it should've been, and tov and CoV was doable. CoV got more doable as I farmed the bricks, but aas will make a big difference as I am basically in eok max aa with just a handful of other stuff, and CoV is certainly tuned to TBL or tov aas, not eok. It's doable, bit would be much better with the key aa lines done, which I'm working on doing stuff I missed in tov etc. Once I got the bricks for my tank, which did help of course, I found they only helped some. Many ppl let aas slide, but there are always key lines that make a world of difference depending on the content you're working in. Of what you're doing now is cake, then try the next expansion. If that expansion raised level, then go for the levels, but if it didn't, you may find some aas are needed for the expansion that does raise level.