That terrain is disappointingly sparse. However, it sounds like you met some cool players with interesting armies.
Terminators in Land Raiders aren't as great as they used to be, sadly. They were always my go-to with my Black Templars.
For command squads, I only had success with 4x plasma or melta, jumping out of a drop pod. A lot of people seem to like super bike squad command squads, which are admittidly better, but that takes points away from Terminators!
I have never had success with jump pack guys. Not even in 5th edition.
All that said, your army is painted well. I especially like the bases.