I prefer BI over the og campaign, but the only thing i dont like about it is how hard it is to get command stars in BI. I had a general who conquered the entirety of western Europe, basically a man of legend and equal to many other military geniuses.... and he got 4 stars from all that.
I've been going through a lot of BI's campaigns recently (just beat romano British and Alemanni) , I find that the campaigns get easier the further south east or north west you go... the celts, romano British, saxon and even alemanni campaigns are not bad, and in the south the Sassinid campaign isn't very challenging. But everything in Central and eastern Europe is an ABSOLUTE mess... I've never seen so many horse archers... I miss my Greek cities with phalanx walls and Cretan archers
If you are playing a faction with less tech for buildings, then you can let your enemies construct those buildings in their cities and then conquer those cities. 😎
Maybe you could try out Diadochi total war, I totally love it (and it opened the gates of modding for me, making my own twist of it, even though I can't deal with some stuff)