I was grouping them together too when I was first reading about the SIII heroes. It took a while for me to understand nuances, the play is very different.
I believe that Jott/Rat are brilliant on titans as you continue tile play and you probably aren’t looking to kill immediately so it isn’t as urgent that the damage is front loaded.
Odin and Frigg do damage then and there which is a huge advantage in a raid/war/tournament.
If I had Frigg she would 100% come along to titans too because she is sooooo much better than Buddy.
Both functionalities have the same drawback when you are attacking; you’ve hunted the tiles to charge them so their color probably will be underrepresented on the board. I was initially very skeptical of all four heroes but am coming around.
Jott is getting emblems and on the titan team. Don’t have the other three but would use them.
Odin and Frigg have impressed me on defense (ok, I’ve only met two proper Odin’s so far so too early to be certain of anything). The first run ins with Frigg were painful because I had been careless with the green tiles.