Yes, verification is a strictly simpler problem, and one that's fairly thoroughly addressed by existing research -- which is why people working specifically on AI safety are paying attention to other things.

(Maybe they should actually be working on doing verification better first, but that doesn't seem obviously a superior strategy.)

Some AI takeover scenarios involve hacking (by the AI, of other systems). We might hope to make AI safer by making that harder, but that would require securing all the other important computer systems in the world. Even though making an AI safe is really hard, it may well be easier than that.