It's a good size for a Syrian. I agree that adding a platform helps for a Syrian as it gives them more places to go and extra space to put toys on. Amazing that the Silent runner wheel fits in! It must be very tight. That is the only slight issue with the Marrakesch for a Syrian is that to fit an 11" or 12" wheel in you need to have very low substrate at that end of the cage. But there is still plenty of floor area left.
It may depend on the personality of your hamster. Some would be quite happy - some are maverick and want more space - but adding a platform should help with somewhere to climb up to
