1v1s, at least for leaders, is only really fun if its 20/25+, the bigger the lines the better as the rounds aren't as autistic where regiments count each others' shots and keep reversing endlessly - leaders can actually go for shooting plays as opposed to just copying whatever the other line is doing.
Larger 1v1s also makes the straight up melees much less cancerous for players too, where regiments can actually form a a line in the melees as opposed to the cockroach drag the enemy away and run which really do drag on.