I don't think giving Agi/Int is the way to go, otherwise it would be the go to item on a ton of heroes. It's a strength item simply because it's basically a "health gamble".
Honestly my issue with current Armlet is that I just get overwhelmed trying to manage it. If you mistime it and are mid toggle, a regular ~300 damage nuke can still fuck you up mid toggle. In a teamfight I'm trying to manage targets, watch everyone and everything that is happening, all while trying to keep track of what my HP is at and how much I have lost while Armlet is on, and what spells have been cast by the enemy so I know when to toggle. If there's any kind of poison thing in the mix (Venomancer, Viper, etc.), I'm even more afraid to toggle it just because the gain isn't instant, and some of the larger ticks can still mess me up. Maybe the only real solution is to load up a practice game and practice vs stuff like Gale, Poison Nova, Viper Strike, Shadowstrike, Poison Attack, etc.
Also it kind of sucks that AA basically makes Armlet worthless.
I played a game as CK earlier, and one of the mistakes I made was picking up Armlet to begin with. I probably could have just gotten more stats and been fine, because I felt like most of the fights I failed at were because of my Armlet.
Then again, you really don't see Armlet pickups very often these days, even in the pro scene. Part of me wishes they would change it back to be instant, but nerf how much Strength you get from it.
I don't think we need to go back to WODOTA TOP 10 ARMLET TOGGLES featuring #1 as an Armlet SF.
instant hp will always be op. Don't bash an item just because of your inability to use it.
You can even say "Also it kind of sucks that AA basically makes mekanism/guadian greaves worthless."