Most competitive alliances do this: one-color tanks. The rationale behind is to have the enemy deplete as many strong tank counter heroes later on, forcing them to use more than 1 war flag against a single enemy team. The more cleanup chore the enemy does, the more likely they will lose that war. As to “wins the day”, RNG still wins.
This is mostly employed by small and non-competitive alliances. I would love facing such enemy alliances during wars. Regrettably, I don’t see them anymore.
Not really, but certain war support does make you feel that certain heroes are well suited for very fast wars. So, if a 30-member alliance, half of them have an Alfrike while others don’t but have decent purple heroes like Ursena, Kunchen, etc., that alliance may opt for purple tanks during VF wars and revert back to their usual war tanks on other war support.
A few months ago, that would be green because of Telluria. Now he has been nerfed twice, but some, if not most, alliances still use green tanks (including my alliance) by reason that they don’t have better alternative since other good tanks are behind a paywall, i.e. Garnet, Black Knight, S3 heroes, etc. Currently, the meta has been shifting. Top alliances are using red tanks for wars, with Frigg and/or costumed Kadilen and/or Odin flanking, and at the wings are Onyx and Cobalt, or Finley and Killhare/Jabberwock.
None. I have deep enough roster of heroes. I use mono. I don’t care which hero is tanking, just let me match 3 favorable 3-tile combination so that I can either kill the tank or the weak enemy hero defending, or both, and finish the job.