Is it fair for Simplified Rules in a turn based strategy game to NOT have Defender's Advantage? Doesn't that mean attacking first usually wins?

The Advanced Rules of my game has mechanics which improve Defender's Advantage. The Simplified Rules do not allow researching any abilities your units don't start with. Currently, "Rolling Retreat" is a researched ability which is necessary in advanced rules, but seems too 'expert level" to be in simplified rules.

What do you suppose I should do about this for Simplified Rules? Without Rolling Retreat, I'm afraid Sword Man will own the early game, and Light "Cavalry will get a Free Win in the middle game.

Updates
11 mo
I'm pretty sure the solution is to just not worry about balancing simplified rules too much. After all, White usually wins in Chess just because they go first. It may be as simple as that. This is part of the reason the LOWEST ranked player always goes first in my game.
Updates
11 mo
musketeers are very hard to defeat when they are defending Forested Terrain. They don't get any penalties when attacking, moving, or defending in forest. The only real way to beat a party of Musketeers on forested Terrain is to light a Fire and burn them out. Troops caught standing on a burnign square take 25 damage at the beginning of their owner's first step of their turn. Forest burns for two turns after being ignited.
Is it fair for Simplified Rules in a turn based strategy game to NOT have Defender's Advantage? Doesn't that mean attacking first usually wins?
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