Looking at Gundam Raphael, major improvements can be hypothesized
1. This gundam would now be a full long range gundam
- It now features giant cannons that looks like it needs a lot of power to use so a sniper scope (like from dynames) is equipped to utilize precise shooting for far away subjects
2. It's not bulky anymore
- The reason for this may be because CB lacks the resources to create a heavy armored gundam with numerous arms to compensate for its bulkiness. Meaning they made the gundam less bulky to increase its close range capabilities.
3. The cannons are detachable
- The reason for this may be because to let Raphael freely move while firing its cannons since Virtue and Seravee can't move while firing its cannons which made Virtue and Seravee vulnerable to side, rear, above and underneath attacks.
- Also, if the cannons are shot down, it might create a large explosion enough to damage the gundam itself, so they probably made it detachable for safety purposes also.
4. Reverse surprise
- Since Raphael is a normal sized gundam and not a bulky gundam anymore, lots of people may have concluded that there's no more 2nd gundam.
- Maybe, instead of showing the bulky one first, they showed the compact one first. Meaning that the large cannon on its back is the hidden bigger gundam and for its name its probably going to be Gabriel
This is all just a hunch :D