I think there's a distinction to be made here between streaming off of your own roster, and streaming using the WW.
I play in a daily-move, weekly H2H league right now, with scoring categories of W, CG, SHO, SV, K, ERA, and WHIP.
The starting pitchers on my roster, who I'll typically start for every start are: Zambrano, Sabathia, Bonderman, Harang, Penny, Escobar, and Perez. That's seven starters, who I'll get anywhere from 8-10 starts out of, in addition to having room to float three closers in there.
I'm not struggling in the least with my ERA or WHIP, and my Ws and Ks are off the charts.
This is discouraged in my league at all, because I'm not streaming off of the WW. In daily-move leagues this is expected. That's why they are daily-move leagues.
If they switched to a weekly-roster league, obviously I wouldn't have room for two (or three) of those guys.
It all depends on the expectations of your league. It's definitely not something that is universally frowned upon.