I can see this game being great in three steps:
- Make the tiles so that positioning of the chosen tiles matters, example: tiles have random score values, some tiles have zones around them (not necessarily squares, make varios shapes like tetris pieces) which somehow power up the tiles in the zone, when the source tile of the zone gets selected.
- Make it so that at the begining of the turn tiles get randomized.
- Add SHORT timer to the players turn
- Profit.
Well, that my take. I can't say anything else than others so... good job you made a working game!