Board Thread:Questions and Answers/@comment-60.231.90.84-20130610042155/@comment-9285337-20130611062935

Yes if you can completly fill the field with the current features, there is no need for additional features to be researched. However note that you don't see the %-figure if it is 100% so if no figure is shown it could mean it is at 100% (which is good) it could also mean that there is room for an additional small feature.

Also larger games have more room for features. So even if your current features fill out for your medium game quite nice, once you make the transition to large or even AAA  games you should have new features ready to inserted into the game.

Yes swapping an older feature in is ok. The way it works is every features has a benefit-value with older features having a smaller benefit than newer ones. (They are listed on the custom game engine page) Depending on where you set the slider of an area there is a maximum amount of benefit-points that you can put into that area. So if you are just 2 benefit-points away from that maximum, inserting that 2-benefit older feature instead of that newer 4-benefit feature will yield the same result in bubble-boost, but the older one is certainly cheaper.