Certainly building good teams is a good strategy for TB.
However we don't really know how multiple battles will be managed yet. It could be that you can reuse all survivors (like GW), or it might be that you use up an attempt for the entire squad and need to refresh (like the ill-fated Tournaments). Or it could be that the squad is left behind to secure that point, forever taking them out of the battle (more like a raid without escapes).
My theory is that as you progress across the map, the requirements for heroes goes up. So you might only need a 1* hero for the leftmost areas, whereas 7* is required for the rightmost. Either way, hero management is likely to be a major component of TBs.
