I actually really like charlemagne campaign, played it a ton already. Its easily in my opinion the best TW mini campaign ive played.
But I'm someone who generally never plays any of the mini campaigns, didnt even like fall of the sam. I thought wrath of sparta was the best rome 2 minicamp (although still pretty bad). much for the same reasons as AoC, its actually different to the main campaign.
but yeah one of things I'm looking forward to in TW warhammer is they are expanding the same main campaign instead of mini campaigns.