Would it drastically affect the campaign were we to discard half of the bookkeeping? Sounds obvious that it would, but we're thinking of creating our rosters at the outset to a fixed limit (150 PL) and using only those units for the duration, ignoring Supply, Requisition and Crusade Points. (which would obviously mean no warlord traits or relics)
We'd still use the Agendas, XP, Damage system.
So rather than representing an escalating crusade where your force can grow, it more represents the sum total of that factions forces in any given arena.
We're thinking of only playing Combat Patrol, Incursion and Strike Force size games, so 150pl gives you a pool of units to choose from, but those units themselves cannot be changed.
Flicking through the rules, and having not played much Crusade, I can't see where we're unduly handicapping ourselves, but there might be something I've missed.