this sounds great on paper but i think it has a lot of problems in application.
1. the phone would be way thicker than what we have now
2. possibility of loose connections
3. the cost of all the blocks you need would be more than a comparable phone
4. sizes of blocks.
5. block incompatibilities. Think, DDR1 to DDR2 and the like.
1. Form vs Functionality, Functionality is what people would prefer
2. the locking mechanism would ensure no loose connections and design should render phone inoperable if there are loose connections
3. the beauty of the Modular design is for owners to buy what they can afford and save up for the Blocks they want, there should also emerege a Market where Blocks can be traded aside from just being sold much like in the DSLR world, not everyone wants the most expensive Blocks since no everyone needs them, owners can just buy what they want WITHOUT restrictions like what Phone manufacturers do
4. to keep the uniformity of the phone blocks should be of the same thickness and adjusts to the needs of the components in them, like the battery or memory
5. modular design alows the ability to adjust to what ram can be used by the system