Winnipeg is looking for a comparable LHD in return for Trouba. For a someone who is sitting and asked for a trade that isn't going to happen, not to mention D are currently at a premium and not many are actually available.
Yes Winnipeg has zero need for Stoner, obviously. Anaheim has a need to get rid of Stoner. Winnipeg doesn't want picks in return but there not getting a player of comparable value so the picks are used to balance value, it can be replaced by a prospect if need be.
Overall it is a complicated situation and the returns are very limited. This may not be perfect value but as a basis it makes sense and considers every teams needs. Make tweeks as necessary, but a young top 4 LHD with some potential + 2 2nds isn't bad value.
Also, Trouba has repeatedly said it isn't about the money. I don't expect him to sign for 5 because its Toronto, I expect him to sign for 5 because Lou can't justify paying him more than Rielly (unless its slight more over 8 years).