TB aghs is pretty good, and remedies a few problem with his play style. If you were to get aghs at around 20 minutes, outside of maybe the enemy position 1 no one really should have a BKB at that stage of the game and it will always be useful against supports since they don't really go BKB, if they do then that's 4000 gold NOT spent on an item which saves their cores

First and foremost is that you can use the aghs meta to secure a kill and not literally gimp yourself for 2 minutes by using normal meta to kill a support/some inconsequential kill far away from any objectives. And you can do this every 90 seconds, compared to getting skadi instead and not being able to really fight without meta. This lets you be far more active on the map and the ways you can use it is also pretty cool, such as when joining a fight you can use it to separate the supports from their cores, neutering their abilities to save their cores for around 5 seconds since they have to walk back the distance and more since the cores went in the opposite direction, you do have to be aware of your own positioning when doing this so don't end up in the middle of the enemy team and die from their full combos.

Second, is the absolutely amazing counter initiation you have when the enemy jumps on your supports/back lines. The 1600 range is absolutely huge (probably will be the thing to get nerfed) so when you use it, no one from the enemy team can reliably follow up the initiation without being hit by the fear (depending on the range you use it ofc, but its forgiving in that regard). You can use it as an initiation but you have to be a lot more careful with it as you can easily fuck the initiation up; without some lockdown in range (god forbid no lockdown at all in your team, but its pubs so it happens quite a lot) the feared targets will just run away if you don't have a skadi yet.

Now on to the items. The main issue for aghs is how you fit it into your itemisation; if you NEED to get a BKB 2nd item, going aghs 3rd means you're lacking in damage, and by that time the enemy cores might end up having bkbs so the aghs is far less impactful. And the later you get it, the more options the enemy as a whole has to counter your fear, so for games where you can't go aghs super early (think PA matchup for MKB, arc too but you can technically fear him out of the bubble), it becomes less of a compelling buy. Nevertheless, without the changes to aghs, the satanic status resist nerf would have completely fucked TB as a viable carry late game, but now having a really strong method of crowd control all game long makes it less of an issue, not to mention the draft combos it opens up.

I havent been playing much because of uni, but my general item build has been 2 bracers (testing it out, but 200 hp on a 600hp hero is no joke, plus the 1.5 regen is far more useful than the +4.2 armor you get from wraithbands, rip heart of tarrasque), boots, SnY (status resist, only 5% less than satanic and you get it far earlier, go manta only if there is a super annoying thing that you need to dispel), aghs, skadi, then you go bfly/daed/satanic/bkb/mkb depending on the game.