She has 0 siege damage. It's an issue.
It's not 0, but it is low. I don't see that as an issue, though. That's actual balance like the hero should be. You trade copious damage for minimal siege and wave clear unless you take the 7 talent.
why would tempo pick up erho?
They want fast results but the talent isn't up for grans so they are just reaching for whatever they can get.
Those are two different situations and that's a highly cynical way to view TS. EVERY team wants fast results. Why is picking up Erho as "reaching for whatever they can get". Outside of Caff he is the best tank in the region and better than Caff on certain heroes. Just because he has some attitude issues doesn't mean it's reaching. That's the cornerstone of the moneyball approach here in our sports. Take a flier on a highly talented player with issues or an undervalued player who fills a specific need, and hope you can mitigate the risks for the benefits.
As for Arth, he was already a huge part of the Tempo drama that caused their blowup. I can't think why they'd want to deal with that again or why he would either.