Is this intentional?
If Tyrael goes full E build and picks Purge Evil at lvl7/
With nanoboost and due to Smite the wicked (lvl16 E) it is possible to cast E before bonus from previous E ends. And look at the damage, its over 1000 from singe autoattack.
I’ve tested it in try mode. If you toggle cooldowns. And attack dummy while constantly spamming E, Tyrael’s damage just skyrockets. I noticed it has a cerain cap. At lvl20 it is 1197.
So the main complaint here is how the auto attack damage increase from Purge Evil persists into the next buff window if refreshed in time (primarily enabled through your level 16 and Nanoboost, otherwise not possible to keep it rolling since it lasts for 4 seconds while Smite has a 6 second cooldown).
Now the math side of it, some might consider this in combination with self sustain problematic in a 1v1 situation but you could ideally stack x4 out of possible x10 which is the cap for the buff. Against two players you might get it to x8 and keep rolling for another 4 seconds at that power level but is very unlikely once you take crowd control and escape mechanics into account.
If you expect to win a game through this alone, you might prefer picking Maiev instead of Tyrael altogether. Was the current behaviour overlooked by any chance? Probably, but crazy things can happen in combination with Nano boost and what this hero can achieve with it is relatively mild compared to other heroes.
It’s such a silly gimmick for which it is hard to reliably get full value out of. Another talent on the level 16 tier has always had almost three times the pick rate over the CDR option. It’s a fun thing and it would suck to have it removed considering how small of a concern it is.
The question is: is this talent synergy intentional or not. Illidan’s W does not stack with itself. It’s realy looks weird that Tyrael can have higher attack damage than Greymane or Butcher.
If you search this bug report section, you’ll see there’s a thread about this long time ago, probably more than 6 months, and none of action took place, so it might imply that this is “a way” how Devs grant Tyrael to be capable of on his aggressive side.
To answer your question, assuming Devs didn’t grant him this capability of aggressiveness, then shouldn’t there be a maximum stack?, instead of that the cap is, to be precise, 9 stacks, as you mentioned, seems intentionally?
Also the text description for Illidan’s Sweeping strike and Purge Evil talent of Tyrael is significantly different, let’s see here
Sweeping strike; Dash towards target point, dealing 119 (+4% per level) damage to enemies along the way. Hitting an enemy increases Illidan’s Basic Attack damage by 35% for 3 seconds.
so, “Hitting an enemy” this means hitting at least an enemy will grant you the buff, no matter how many you hit, the effect won’t be stacked.
Purge Evil; Each enemy Hero hit by Smite increases Tyrael’s Basic Attack damage by 60% for 4 seconds.
This case is “Each enemy Hero hit”, that means he’s capable to get stacks from hitting heroes, in fact he can reach his 9 stacks to this point but his E CD still restricted him to do so, 5 stacks for hitting all enemy is the maximum cap till he reached his CDR talent at lv.16, if he get some kind of CDR from someone else, for obviously example, Nano boost, then he can time to use his E to stacks to 9 stacks.
last but not least, Tyrael is a “dive tank” who barely have significant CC abilities, agility and assault are his strengths.