1. Yes, that is intended. Legendary towers and items are sometimes double-edged or complicated. 2a. Loki can be an ok carry, but he requires a bunch of luck. An obscene amount of luck. Other carries are usually better, but it can be a fun way to play. Lucien as a hero multiplies the effect. 2b. Thor could potentially be good, but his base stats and effects are unlikely to compete with towers that have a built-in scaling factor, like poison frog's poison, scarecrow's crows, etc. I have not tried Thor on a very strong late-game build before. One aspect is that with very slow speed, he can benefit from more bonus attack speed before he reaches 0.01 sec (min) speed.
fully agree to fuzzy. in my opinion, thor is the 2. strongest tower at this state of game (after frog), because of his hilarious base-damege.also eldritch chainsaw would make him a vaible carry, even with negative speed add. due to his 4range he could be benefitial against vir. swapping frog to thor or vice versa, dependent on positioning. https://ibb.co/nBMh2F6 i wnanted to check his base-damage chart, so here an example