And tactics really do matter. With the right strategy, you can defeat opponents with significantly superior forces. By the way, I'd like to suggest trying out duels. In a dozen games against a strong opponent, you can learn a lot about tactics.
As for the sixth installment, honestly, I'm not too concerned about how characters look. What's more important to me is balance, and it would be nice to have more alternative upgrades for creatures and to add around 20 skills (instead of 12). All this would add variety to the possible tactics.