Modular, it’s both very simple and very complicated.
It’s like a wedding reception: you can choose the venue (a dream case), you invite whoever you want (some cool modules), each can be placed ‘just about’ anywhere you like but be careful: you have to make sure that everyone will have enough to eat and drink (power requirement), otherwise you'll spoil the party!
Ah, also, anticipating the outs in the ins, being far-sighted ;)
'On ne devrait jamais quitter Montauban' (Fernand Naudin).