Omni movement is largely a nonfactor in PVP. You can forget it exists and be fine. Pretty well implemented IMO because you don't have to use it to keep up with the cracked sperg teenagers. Most times it's disadvantageous to use it. Diving around is mostly pointless, but it is fun to do for the lolz or the action movie moments (like diving out of the 2nd floor windows in Nuketown). Sometimes you can catch someone off guard with a dive or by staying supine in a weird spot. Otherwise the movement meta hasn't really changed. Sliding/slide cancelling is still king. Being able to slide laterally is probably the most useful omnimovement tool.
If you have enjoyed previous CoD's, it's worth it if 2/3 modes interest you. Between the campaign, zombies, and MP, there's a lot of content to grind.