I'll also allow myself a small comparison... but it will be fair and balanced.
Personally, I think the caravan is a very successful feature of 4. It' same not present in 3. And that's why it often causes me inconvenience. On the other hand, a big advantage of 3 is that you can sell an artifact you don't need. In 4, you get a large number of different and identical artifacts (more than in 3, it seems to me). You need them to varying degrees, but you cannot sell them. And money would come in handy...
And 5, in my view once again, is just great graphics. Any game would envy it... Don't judge too harshly.