My top 5 would be a bit subjective. Some would benefit fish more while others would benefit the angling experience. Here is what I would do:
1 - Develop a spawning escapement goal for both pinks and chums and implement it. Currently there is no target escapement, no estimate of current escapement nor any ideas of what the watershed should be able to support based on habitat.
2 - At present there are several groups as well as government, spending significant amounts of dollars to remove large river obstructions ( boulders ) preventing salmon access to the 40 + kilometers of habitat in the Elaho River. This is the best habitat in the whole watershed especially for chinook, coho and pinks. This habitat has recently been made accessible but with current salmon population sizes it's going to be a while before it's colonized in any significant way. What is needed is a fry stocking program to utilize this habitat until returning salmon can colonize it on there own. Coho stocking would see the most immediate return from this.
3 - The water ramping rates on the Cheakamus River downstream of the BC Hydro dam need to be totally changed as the flow changes are currently too rapid. Lots and lots of juvenile fish as well as adult pinks this fall were being killed by a too quick decrease in water flows. Groups are working on this but there seems to be lots of push back from BC Hydro on reducing the ramp rates. This is a major fish killer in the watershed. This also applies to the IPP projects on both the Ashlu and Mamquam River.
4 - There needs to be a significant revision of the amount of fishing guides on this watershed. It has gotten a little silly in the last few years with guides coming from as far away as Pemberton and Mission. Combine that with the amount of assistant guides and the pressure gets a little silly. A good example of that was a guiding company who will remain nameless, was bringing up full bus loads of people this summer to target pinks. There has to be some control on this.
5 - Currently there is a small pink salmon enhancement program on the Cheakamus ( 1. 6 million fry ) that will likely disappear next cycle due to reallocation of priorities by DFO. This program was one of the things that helped rebuild the pink population after the CN Rail Caustic Soda spill in the Cheakamus in 2005. This program must continue as it is a good tool to use to maintain a pink population after one of Squamish's major floods that were famous for. It would also serve as a excellent way to have a returning pink population that can be use to colonize the Elaho with pinks. In a cold and glacial system like the Squamish, pinks are a superb fish that provide essential nutrients for the watershed. Char and juvenile salmon are always fatter on a pink cycle.
So that is my top 5. There are other things that I would like to see happen but I know there extremely unlikely ( steelhead issues, Johnstone Straight mixed stock chum fishery ) so I would be happy if these got addressed. So put that in your pipe and smoke it.