Some excellent points of view here. For my two pence worth (point of view... not a fact.) Zenimax and Bethesda are one and the same company, just a different arm. Zenimax looks after the online stuff. But if the proverbial hits the fan, then Bethesda will be impacted. Bioware are releasing staff and are very aware that SWTOR has not been the cash cow they had hoped. Subscriber levels have dropped dramatically. No game enthusiast should take pleasure from their struggles as it impacts the industry that we should all hope will remain vibrant and successful. Slavishly copying WOW has been a mistake, the mechanics and cartoony world of these generic MMOs are losing their appeal ( and subscribers) quickly. We can but hope that ESO will have something new and innovative but from first reports it does not look good. Developing ESO will take massive amounts of money, if it is not successful then Bethesda and future releases of TES will most definitely be affected.
EA reported before launch that SWTOR only needed 500,000 subscribers to be profitable (the game had 1.7 mill and is now at 1.3 mill, which is better than most MMOs), so the game is performing well over what is needed. Many who actually play SWTOR realize the issue isn't because the game "copied" WoW, but rather it was not ready for release. All the standard features one expects to have in an MMO, like WoW, were missing and BioWare is desperately making a mad rush to implement content.
In regards to ESO, anyone who has followed an MMO in the past should be well aware that judging a game we know very little of is silly. We won't be able to criticize this game until we actually get hands-on and are beta testing it. For me though, the reason why this game is so appealing (obviously it's TES) is because of ZeniMax Online's determination to make a truly social game (which many MMOs seem to fall short on, older generation MMOs were better at this) and a gameplay based around tactics and not a key rotation and gear. Those two features alone are keeping my interests heavily. I could care less about the graphics and the stylistic art direction as any MMO vet knows such elements become irrelevant in the larger scheme of the game (look at WoW).
That being said, ESO is part of the TES franchise now. So as you stated, this game will impact the rest of the IP. Even if some TES fans aren't on board for this MMO, the last thing you want it to be is a failure, as it's uncertain what kind of repercussions could befall BGS in the fallout. ESO is off to a great start, considering it's based off a very large and popular gaming IP and has a 3-faction world pvp system many know and love.