I wish you luck entering this market. There is definitely room for more competition, but the big problem is the rapid lifecycle of cameras, the large number of systems you need to support, combined with the small market. This means that any given design will only last a couple of years before the next great camera comes along and makes the design obsolete. This implies that the total manufacturing run of any given housing will be small making it hard to achieve economies of scale needed to drive the price down. If you want to distinguish yourself, you need a new approach. The thing that kills existing housings is that when a new camera comes out, the manufacturers feel free to change the form factor and button placement.
I think that to succeed, you need one of several approaches. One is to design a traditional style housing and drive the parts cost down enough that you can compete on price. Another is to offer some new feature that no-one else offers. The other way is to "future proof" your design so that you can quickly adapt to new cameras without a huge expense
I think that there is an opportunity right now by breaking with the traditional design and eschewing the mechanical actuator and going to electronic controls as is common in video housings. One benefit to the user is a more ergonomic design, but the benefit to the housing designer is that you are not so closely tied to the whims of the camera manufacturer as to button placement. This is part of the future proofing I was referring to.
And whatever you do, make sure that you deal with some of the obvious design flaws of many current housings. In my experience this includes:
* A simple way to balance the housing. I would include some sort of sliding counterweight system as is common in video housings
* A simple port lock that prevents "accidental" floods
* Robust o-ring system that doesn't flood in the rinse tank. This means don't rely on suitcase clamps which "seal better" at depth. The seal should be just as robust in the rinse tank as at 100ft. This is simple to achieve with the traditional face seal described in the machinist's handbook. A side benefit is that it would be less likely to capture dirt on shore dives, and would allow the use of compressed air to clean the salt water out of hidden spaces.
* Strobe connectors that don't corrode.
Lastly, and most importantly, LISTEN to your customers. There are a lot of smart people on this board with thousands of man years of experience. You and your staff, will have at most a few tens of man years. If your customers tell you something is a problem, there is a problem. I know that I have fed back a number of simple, inexpensive, design improvements to my housing vendor and all of them have been ignored