Regarding the pattern system it’s way more flexible on the MC than it is on the MD itself. It’s a bit difficult to explain as it’s kind of complex.
On the MC you save slots that contains the sound and the pattern of a specific track. When you enter the save slot menu by hitting fn+yes you have the choice of saving just a specific slot or all the slots at once which basicaly is the equivalent of a pattern. Those slots are organised in rows on a grid. One row = a pattern that you can access with the bank and pattern buttons juste like on the MD system.
But now you can mix and match different slots from different rows as you can load slots from any rows via the arrows button. You navigate through you pattern in the grid and choose to load one particular slot of one specific pattern. You can also chain slots.
It’s a bit overwelming at first but then you realise how flexible it is. And you you can also just use it in a more linear way by just saving and loading entire rows which is the equivalent of saving and loading a pattern + a kit.
The kit system is now a bit less decisive because the sound informations are contained in the slot/row system. It also makes the song mode a bit irrelevant.