I have steam but I do not have ESO on steam because I started playing it before ESO was on steam. With all the problems ESO players have had with steam in the past, I am very glad I don't have it on steam.
Steam/No Steam...I have both and don't really notice a difference. My ping is always around 75 to 90. Maybe check your DNS servers? I use the Google Public DNS ( 8.8.8.8 and 8.8.4.4). Hope this helps.
I can't understand why anyone would use Steam if they had any alternative. I have it for Skyrim, because it's the only way it can be played, but if there was ever an option to play without it, I would.
Giving a third party the ability to withhold your access to a game you didn't buy from them is just nuts!