Before this derails into bait and blame games...

Its both. PVP-oriented changes are highly visible because its not like PVE bosses have forum accounts to complain about overuses meta sets and power creep.

PVE population is higher, helped by ZOS driving away lots of dedicated PVPers with years of failure to fix persistent performance issues.

ESO is really two games. PvE has the larger world area and player base. PvP side was designed to be standalone to the point that someone that only wants to PvP can fully level without ever leaving the PvP side of the game. I think the acrimony between the two comes from primarily two areas. First, the game tries to balance combat across PvE and PvP. All too often the result is fixing balance in one breaks the other. I fell this one would go away if ZOS would just admit they need to balance the two environments separately. The other is largely due to the way events are structured that has been exacerbated by the event ticket model. Most events are standard PvE content but there is a PvP event that awards unique items as well. None of the events or their content provide items that are needed to play the game but they are unique and some players on both sides get upset they have to run the content to obtain them. The addition of event tickets make it worse as a player might decide they just won't go after a certain motif or buy it instead where event tickets tend to have more appeal for the prizes they offer. I don't know how to resolve this other than offering a PvE and PvP option for every event much like IC having PvP in IC and a PvE option for the IC dungeons.

There was a recent poll, for what they're worth, that showed a little over half of the people that voted did both. That of course is forum goers not really informative.

No doubt more people PvE than PvP, but to what extent is unknown.

At this point I think the devs use a Ouija boards for changes.

PvE. Dev team tends to ignore PvE entirely and tweak things based on PvP whining, but the game is first and foremost PvE.

PvP is basically one area, one game mode where teams compete in predefined matches, and one "PvPvE" area that is a complete mess and failure, as every things on that theme have ever been in the history of gaming, because they don't cater to anyone specifically and end up being rather unused. Except in the case of the current event, that is.

PvE is basically the whole game, minus those exceptions. 15 base zones (5 per alliance) + mini-zones that used to be starting areas (5 of them) + 4 DLC zones and one to come by the end of the year ; so that's 19 zones + 5 minizones + 1 zone coming soon. And I'm not counting dungeons and raids there.

So, as expected of any Elder Scroll game worth its salt, the focus is on you adventuring, not beating the snot out of some other adventurer. But the minority of so-called "competitive" kids who whine all the time about nerfing this or that because they can't even be bothered creating their own builds and can't cope with anyone who devised a counter to their copy-pasted setup certainly is extremely vocal.