TES series is about wonder and discovery. The satisfaction of working on skills and honing them in a way that suits your playstyle. The feeling of seeing something amazing and feeling like nobody else in the world has ever seen it.
This game will suck the very soul from the TES series.
I can see it now. Running to the bank to deposit some materials I had to grind for by killing wolves, and seeing a group of players fighting a dragon in a non-cinematic slog, as tiny numbers appear above their heads for damage.
What I loved about the single player elder scrolls games was that you can start a new game, choose a direction, and walk. You're guaranteed to find something new and fun. With the addition of levels (unlike the scaling levels in TES single player) you will be locked into small corridors you must grind through to get into the next area. Then, previously discovered areas will be boring because they are below your level. It's really sad. Tamriel is going to be a sad place.