OK, a few thoughts on the traveler issue, and on the line Laser style traveler too (it's along the same line so keep reading).
First, the wave is not a high performance machine with detailed mast bend/rotation control... ...it is at the other end of the scale, it is intended to be simple and sacrafice some "performance".
That said, I added the traveler to the boat because the lack of basic sail control was driving me nuts. It does allow me to adjust the sail to make the telltales fly from top to bottom, and on windy days it allows me to travel out to sheet the sail more uniformly (control twist). In these windy conditions, and on broad reaches on any day, the ability to travel the mainsheet out may by a small margin make the boat faster (again, more uniform sheeting). It's all about twist control.
In order to sail with the sail "tuned" for any angle of attack, the traveler is set, and then the mainsheet is played to adjust for small wind changes and accelleration/decelleration.
If you stand behind the boat on the beach with the boat sitting on a "close reach". Sheet in slowly with the mainsheet centered. Look at the top of the leech versus the bottom (back edge of the sail). Notice how the top of the sail "twists"? Now, if you can move the mainsheet attachment over a few inches (travel out), notice how you can reduce the twist in the sail and have more uniform sheeting and more tell tales flowing? This is what it is all about.
The Laser style line traveler will not work well on this boat. A line traveler on a Laser is usually kept tight allowing the mainsheet to travel to the leeward corner of the boat. You can "center" the traveler by loosening the traveler line. This is seldom done on a laser as center sheeting is slow. On the wave, center sheeting is normal from close reaching to beating (or when teaching sailing and ignoring the traveler entirely as a traveler is one more detail not really "needed"). Additionally, with most rigging the boat with maximum mast rake, there is not room for additional blocks or line streach seen with line travelers.
Also note, although the Laser and the Wave are three to one purchase, you will never sheet a Laser nearly as hard as you sheet the Wave. This is another reason why if you use a traveler, you need a fixed version.
The issue of reefing is totally different. A zipper reef will reduce the amount of sail, a traveler will allow you to sheet more uniformly, feeling less power, but at some point, no matter what you do, a full sail is too much. It's easier to understand from a windsurfing perspective, you can try to sheet out all day long, but at some point, a smaller sail just works better.