Nice!! That looks really good, definitely more roomy inside than the Trixie. I also prefer the way you did the lid so it sits securely on the house, I find the Trixie lid can be a bit wobbly. I think just the three chambers are fine, that little one under the ramp never gets used by my guy anyway (mostly because he can't fit properly in there). I also like the big chamber in the middle so at least he's got space to turn around, if you divided up that chamber it would make it too small inside I think.
I think the suggestions about the top opening and a little ramp are good as well. I often find my hamster will block off the bottom entrance and just use the top one. I can't really tell from the pictures but are the openings for the hamster to get through bigger than in the Trixie? If so that's fantastic for those of use who have hamsters with more 'junk in their trunk'
. The only thing about the ramp is that it does use up space inside the house and would use up one of the chambers, but then personally I like having a top entrance. I don't know what would work better. Maybe make it even longer and add another chamber to the side? Not sure how practical that would be though