Discussion about Sylvan (Wood Elves).

2) Not on medium levels – attack the enemy with strong creatures, and defend less against those attacking the archers.

I would rather use even the weaker creatures to their full potential, as you suggest. I wouldn't put the weaker creatures in defense; instead, I would use the "wait" function to find the right moment to attack! And you should also use the archers and druids.
P.S.: Putting all the weaker units in defense when fighting neutrals is not very effective.