RE: What makes a pattern plane?
When I was considering starting pattern, I talked to the pattern folks about what I should get. At that time, I was flying a Goldberg Tiger 60. They told me to get the Sportsman category pattern program (flying sequences) and practice those with my Tiger 60.
That plane is fully capable of doing all the basic maneuvers required by the sportsman category (beginners level pattern) and, in fact, has been used by pattern beginners in competition, and quite successfully, I might add.
It is not an expensive plane, but is large enough to be quite visible and, if built straight, will do all of the maneuvers with authority and will do well to train you to move up to the next category, intermediate. Then, you should be able to consider a true pattern ship. One that I would suggest at that point, is the Venus 40 or the Venus II. Both are very easy builds and very VERY capable pattern planes, and will not bust the budget.
But, as I said, and as other replies stated, your focus should be to learn to fly a low wing performance plane, then to get started in the basic aerobatic maneuvers required by the Sportsman category, and an ideal plane to do that is the Tiger 60, or something very similar to that.
Remember, though, just doing the maneuvers is not enough. You must be able to take off correctly, make the appropriate turns that are clearly smooth and purposeful, fly straight (not as easy as it seems) then setup for maneuvers. All maneuvers in all categories are done in sequence and must be done that way. It's not easy, and takes a lot of practice. Be prepared to burn a lot of fuel.
CGr.