I think the Paris-Cherbourg complexity issues were when there were a limited number of Turbotrains in use in the 1970s-80s. They didn't have enough capacity for travel peaks, so instead of the UK Privatisation approach of "tough", there were loco-hauled Corail trains that supplemented or replaced them for all sorts of peaks, Friday afternoons, August holiday traffic, public holidays, etc. Each was different.
The French have always been good at scheduling for peak traffic, although other aspects can let them down. Having seen on an August Saturday afternoon an arrival at Paris Gare de Lyon of two coupled double-deck TGV Duplexes from Nice, followed about 4 minutes later (fortunately not on the opposite side of the same island) by a relief of the same formation, everyone with holiday bags, the station was still absolutely swamped half an hour later with queues to get in the Metro, no taxis, etc.