Shen can't be viable or strong, not with his current ultimate.

im afraid that when he does get reworked one day they will keep his ultimate just like with kassadin because "muh identity"

It goes pretty much like this, if shen is winning top then he is winning top,mid,bot and preventing your jungle from pressuring enemy jungle. That is outright unhealthy, it just is. You all in mid and shen stops you, you all in bot and shen stops you with either ult or TP.

Shen can't be a strong pick, he is practically the IDEAL toplaner, someone who can splitpush effectively all day and have 2 ways of helping his team and preventing the enemy team from making any kind of comeback is going to be a loved thing by any competitive top lane player.

Think about poppy, you don't want her viable or strong; she is effectively the best assassin in the game due to 0 counterplay instakilling while the enemy team can do nothing and watch.

tl;dr keeping identities doesn't work out all the time, when champions like kassadin,shen,akali etc get their big reworks they can only be fully balanced when they don't get to keep the toxic parts of their kits.