As far as I know, improvements to this system are planned. There are ideas in which only players who leave the game will loss TP (if they do not return within a minute), and the bots will not buy items.
I pretty much liked all of your changes to items except the one you made to invisibility. I liked it at first but now that I think about it Im against it atleast for now. I see alot of problems with the new mechanic like when EM made their last balance changes to stealth, they made it so that hitting shots at them would show dmg numbers while invisible. If they have good awareness they can track you down much easily unless that change to dmg numbers gets reverted. Skye as a flank was meant to counter Kinessa but with this change She will just become one of Skye's possible counters even if the stealth change EM made gets reverted especially with the mobility Kinessa has(and she may see u long range with scope) while Skye doesnt have any of that or enough speed to compensate. It will also make her Preparation talent useless. Maybe make it so that her stealth in smoke bomb cant be seen in any way while moving. Sha lin ultimate is going to be gutted with this change since you have to move frequently to make use of it and dont forget dealing dmg pops numbers on stealthed players. The champs may need a buff on top of all this.
About stealth in general, people never complained about it really, they mostly complained about illuminate being too strong against it. If the change goes live Skye would need a heavy speed buff in her base kit with stealth. For Sha Lin, a champ I dont play, I would suggest making his stealth during his ultimate specifically completely ignore your changes but make it so that he is revealed when charging his bow instead of while firing if illuminate is removed. The invisibility changes feel like it will bring more harm than good imo but if you can convince me the change to invisibility is good then ill vote for it. The other item changes are pretty good to me.