Of course there is a way to change anything. But you must carefully think over the changes you do. The source code is available here. Here are some directions:
Blocksize to increase it?
Change the MAX_NUMBER_OF_TRANSACTIONS constant
Block timing can this be increased either along side blocksize or separately?
It can be increased or decreased ...
I spoke with Bas and he mentioned that like with mining, the coins themselves aren't really sent but rather generated, in a similar manner with mining on Bitcoin. Because of this, there are no fees involved.
Regarding sending out the currencies though, they will need to have the native coin in order to send it out. So with Nxt, this would mean that the ...
Please refer to the official monetary system documentation https://bitbucket.org/JeanLucPicard/nxt/issues/205/monetary-system-documenation section "Currency Exchange".
The NXT wiki also has an excellent walk-through of the process in https://nxtwiki.org/wiki/Monetary_System#Exchange_an_Exchangeable_Currency