It's not so much the optics as it is positioning...getting to that perfect spot where you can kill unsuspecting infantry leaving the spawn room in an attempt to fight other infantry. That's what matters.
If you play conservatively then 2x zoom, it is pretty easy to see and hit even at maximum range for that. Thermal doesn't really help at that range, and closer it is easy enough to see. Maybe Thermal if your playstyle is more charge through the middle (al la Harrassers), but I don't think you'll live long doing that.
It's a tough choice really. At zoom ranges, if you're good at adjusting for the projectile drop, you can snipe a lot of infantry on towers and such from much safer ranges. But the thermal can be a major asset for finding infantry, especially at night and in smoky conditions (smoke is getting used a lot more maybe due to UBGL use or maybe it's just a connery thing to spam smoke IDK).
Well you should cert both if you can because using tanks is situational. Examples: 1) You are sniping because enemy would blow you up if you get closer - Zoom is the choice (thermal has a short range so you see just black in distance) 2) Crowded area or area with a lot obstacles like Indar SE area - thermal will be helpful to spot enemies putting their heads up etc. 3) Shiny day on esamir - dont even try to use thermal or you will get blind. So you see there are plenty of situations. I would start in certing the zoom to 1.75, then thermal
Thermal. On mid-long range, you'll be missing a lot of your shells, so zoom is pretty useless if you ask me. Get close and personal, with the aid of the thermal (ooh, it rhymes)
Thermal. The only weapon for Lighting where zoom imo is useful is the Skyguard because most of the time your targets will be out of thermal range and all other weapon for the Lightning are good for AI, if going AV then your target should be big enough anyway that zoom is not required
