If han is the fastest on your team, his taunt is probably wasting a lot of TM on your other fast toons. If he is slower, his TM will give an instant second turn to your faster toons plus get ur slower toons to fill. You have to tailor ur ST for ur needs.
Speed totally depends on your server and ur team. My han rocking out at 140, atm. Have had him up to 190, and that was pretty awful at that time. Dropped like a rock in arena.
People easily beat a one trick pony. Especially when that pony isn't even particularly good at its trick. Lots of teams have a faster first turn attack pony than speedy ST Han.
If u wanna hold rank, u probably better with an RNG defense than a high defense against one or two other squads. People.will go out of their way to attack a squad they know they will beat 99%. If only because it is hard to pass up a match where ur squad happens to shine like a diamond.