Just the other way around, a tighter strap will slightly reduce the shock travel but flatten the approach angle. The steep approach angle makes the sled a dog in the deeper snow, it just saws through the snow rather than get up on top. For jumping, it really doesn't matter, having the extra 1/2" of shock travel may help but if your going to bottom out, the 1/2" probably wasn't going to change the world. Really you have to just try things out and make changes one at a time. Just remember, write down were everything is at now, then document each change as you go. If you have a smartphone that's a good place to make notes as paper and pen get a bit tough to deal with on the trail. Also, If you tighten the heck out of the front strap, the sled will be biased to the front, so you may need to either stiffen the front shocks, or tighten the rear of the skid, you can add a strap like the Nytro has, of soften the rear springs a bit. It's a balance, you would be amazed at how much better a balanced sled with softer springs can deal with large hits vs. a supper stiff rear or front only.
The Phazer is pretty top heavy as it is, so lowering the ride height will greatly improve the carving ability as well. It won't have as much of an abrupt feeling when leaning.