Yeah that trade proposal was garbage. A few things to note.
First, not sure why NYK would trade for Rondo when they can sign him in FA next season. Rondo and Melo have talked, I'm sure that Rondo doesn't want to go to a team that is giving up nearly all of it's limited assets in return for him. The Knicks made that mistake with Melo once already. Melo was probably going to NY either way. Not sure why they had to mortgage the future of the franchise to get him.
We already have about $34M in expiring contracts next season. Adding in Amare and swapping Rondo/Wallace actually makes that number increase. Having cap space is nice when people want to come play. That will probably not be the case. Gasol, Aldridge, Rondo along with Lebron/Love are next summer's big fish. I think we have a realistic shot at signing one of those guys. Care to guess which? Other notable FAs include Millsap, Deandre Jordan and Rudy Gay. I'd hope we'd take a swing at Gasol in FA but honestly at least 2/3 of the league is going to do that. You think Gasol is going to choose Boston over NY? I'm not even sure Rondo is going to do that.
Lastly, I think there are better trades on the table for Rondo. I think LA would probably give up Randle and possibly a 1st for Rondo. A trade with Detroit around KCP and pick(s) might make some sense. Even Dallas/Houston have more draft assets than the Knicks to make some play for Rondo. The Knicks are one of the most asset poor teams in the league, along with the Nets. It makes virtually no sense to deal with them and as I mentioned before it doesn't make a ton of sense for them to deal with us.