They have a good experienced guard in Dennis, and he should be used and play more time.
No question about his capability, he really is a good guard, his team won the FIBA world cup, right? However, even if Dennis is good, he can also be a liability if their opponnents will design a play to attack him since he is a small point guard, so Raptors also need to look at that, I see Dennis as Trae young who is a liability in the defensive end.
Raptors now ranked number 12, so I think every game is important for them to at least qualify for the play-in tournament. However, missing Siakam might be a big problem for them and it started to show their real capability as a team.
Trading Siakam will create a long term problem to them especially if they want to compete to get a slot on playoffs or even in play in. But if they don't have any aim for that since they want to rebuild their team then I guess taking any extra steps is not necessary anymore especially they only got role players in return. I know brown is really a good player but for sure he is not in the same level with Siakam which is good on defense but also can contribute on offensive ends.
Every game is really important for them but I guess they struggle more to compete especially there are more great team than them in the east.