IMO Newtrox's ult is the worst part of his kit
His Q takes some serious skill to get down, but it's very rewarding when you do. His ult revive doesn't help at all and is greatly holding him back.
Dying cancels Q animation and it is guaranteed to go on CD while you're reviving. When you come out of the revive you don't have your Q, probably don't have your passive, W, and maybe one charge on your E so you're a sitting duck. It leads to a death almost every time. The only time the revive is useful is maybe surviving a gank, tower dive, or a really close 1v1. Otherwise you'll be using the ult almost exlcusively for the MS and the AD.
I (and many others on r/aatroxmains would rather have his ult give more stats, improve the AOE on his abilities, or have him get more base stats instead of the revive. Riot has made it very clear that they aren't very interested in preserving the identity of the champion, so why not take it one step further and allow the current champion to be the best it can be?