I wouldn't mind if inventory increased few slots, but it makes it more of a challenge to only take with you what you need for the time, And sence we don't need any material for repairing stuffs i think the inventory space is working just fine. prepare abunch of empty portals that you can activate at any time when you visit islands and need a quick way back. I just recently put up 6 portal i named "Random 1-6" just for this cases,