To be honest Paper2D in UE4 is really a powerful tool to make 2d games and the thing is I won’t recommend you to move to unity or any other 2d game engine cause if you start with UE4 to make 2d games you will find all you need is your creativity to use blueprints to make your 2d game …they already have shown it you can download 2d game samples from UE4 Marketplace. btw if u move to unity or something it won’t make any sense but u stick to UE4 I am 100% sure in every upcoming UE4 updates u will find its getting better and better in providing tools to make 2d games and at that time u will find u are able to make 2d games very quickly and easily. UE4 is the future of 2d and 3d games. and imagine if u want to make VR games …u have to pay 1500$ for unity and for UE4 nothing. SO GO WITH UE4 without any doubt.