Its very little like WoW. STO is quite combat centered, which may turn off some people who were hoping for more of a simulator style game for role playing. Most of the time you destroy enemy ships or you beam down and have a fire fight on the ground. Occasionally you perform some scans to investigate something.
Where the game shines is its "story episodes". I don't want to give too much spoiler but you might just revisit a very famous location from original Trek and go on an epic journey to rescue the descendant of characters we all know and love so you can save the Federation. These types of missions have different stages of space dogfights, away team missions, warping to new planets to follow leads, etc. that make them feel very much like you are participating in a TV show episode. Cryptic promises more of this to come but to be honest I feel they are leaning on the repetitive content to get the game out early. If you are concerned about not enough of these types of story oriented missions I would wait a few months for them to get some big content patches out because they have already announced some big stuff coming.
I don't care for PvP so I didn't do any of that and can't comment on it. What I can say is that I tried for a week to convince myself I didn't want to get it until they had some patches out. I just couldn't stop thinking about the game so I ended up buying it after all.