Comments are as follows: interesting idea. A few things I'll suggest improving: Researcher {Replace the word "science" with something that fits the Swords and Socery/Fantasy Genre-there is no 'science' ability}
Improved RMMPL {wordsmithing suggestion}
At 10th level, your customization *builds' damage* increase by one damage die and you can use them up to 2/LR.
Improved RMMPL {wordsmithing suggestion}
At 18th level, you can apply two customization builds to your RMPPL and *they increase their damage by another damage die*. You can now can now use them up to 3/LR.