Spoilers will give you forward lean, but there are other factors involved. Depending on the way the spolier is attached to your boot it may take up space and compensate for skinny ankles, or simply exend up the outside of the back of the boot and force you forward while not allowing you to stand straight up. Old long skis required you to throw weight on the tips to make them turn, so old boots have more forward lean. Current model skis are made to turn more from the middle of the ski, so newer boots tend to be more straight up.
Racers like forward lean and spoilers because it keeps them forward, allows them to rock back and accelerate out of a turn, and quickly climb back up on their skis if their weight does get back. I don't know about you, but I generally like to slow down when I turn, not accelerate, so it depends on what you are looking for.
I have always thought the key is what happens when you lean forward and back in your boot. How far to you have to go before you pressure the front of your boot? Do you want instantaneous contact (like a racer), or a more progressive move to pressure your tips. Maybe you just need stiffer boots. Same thing going back. Your skis will always accelerate when you get a little back, but how fast does that happen? How much boot leverage do you really need to climb back up on your skis from the back seat?
It really depends on your body type and skiing style. I like to hang on the front of my boots during a turn (old school style), so I use heel lifts and less than the stiffest boots. It feels more like a tele boot than a alpine race boot. My spoilers are adjusted down as far as they go so that I can staighten my leg between turns and relax. Some skiers like a more solid fixed (less forgiving) feel where any slight move forward or back gets an immediate response.
I ski from my tips, so to me "working the tails" is a desperation move when I missed the turn the first try with the front of my ski and am trying to save it on the back, which is why I prefer soft tail skis which allow you to actually work the tail into a turn as opposed to just accelerating staight. When my weight occasionally gets back stiff spoilers or stiff tails only cause problems.
I can ski any kind of condition or slope without big spoilers, so I think they are a hinderance more than a help. But then the new guys are throwing some moves with techniques that may require them. I am sure that they help when skiing backwards, but I am still working on improving going forward.
Putting spoliers on or up will definitley change your skiing, but if all you need is to stay more forward to improve your skiing, you can do that without forcing the issue. If all you want is forward lean that can be accomplished several ways without a spoiler, like heel lifts. I also loosen my top buckle a notch when skiing steep bumps, which allows a little more forward lean.