No. Golf was never suppose to be about distance, its about hitting shots. up, down, left, right, hook, slice, fade, draw, punch, lob, chip, knock down (stinger for the kids) putt. Its about the shots. A par 3 course can be as challenging as any other course
It depends on your skill level (handicap). I had the same problem with my old set. Good distance progression up to the 5 iron, then they seem to all go about the same distance after that. Now I carry PW-6 iron, with a 4 (23 degree) and 2 (17 degree) hybrids. The hybrids made a world of difference for me. I could never feel so confident with a 4 or 2 iron.
For your second question you would have to try them out and see. I have a 20-30 yard gap between my 6 iron and 4 hybrid. I was thinking about a 5 hybrid myself.
I got Nickent 3DX RC hybrids (2008)