That's a viable alternative!
I tend to stick to tradition. If I can manage to get a good number of ducks and angels with Tazar, he seems to be the stronger choice. As for Wistan, in SoD, he can potentially get up to <20 bows in total, which is a risk. Although, on some maps, he might have a better starting position.

P.S. Another trick for the swamp:
Thanks to the fast dragonflies, hit-and-run mages become very effective. In one of my games, I got Andra, so I focused on magic skills, learned Bolt in the secondary skill, and gave her a slight boost in the beginning. By the end of the second week (as far as I remember), I arrived on the opponent's territory with 7 groups of dragonflies. I had around 150 mana. Strength 8-10+spellpower:) Now, if someone attacks me, I eliminate the archers and then pay them off. If there are no archers, I have a good chance of casting a double spell. A random hero attacked me with 20+ griffons and other units. I slowed them down and destroyed his entire army. The main hero attacked, I cast Bolt on the archers, and then, feeling satisfied, I paid him off. The game was decided.