I'll start with the bent handles. It has nothing to do with Daiwa- they had nothing to do with inventing it. The bent handles move the center of mass of the reel inward, as well as torque, and change the drag star clearance. Shimano doesn't need to do any of these because of the configuration, therefor there is no need of the bent handle.
EVA knobs would be far less durable, or comfortable, than the septon grips that Shimano uses already.
Shimano does utilize promotions from time to time, however, a large part of the reason those promotions are run are to get people to buy the product for the free stuff you're giving away. When you are already one of the top selling mfrs in a category, people are already familiar with the product and there usually isn't great need to sweeten the deal, if you will, to make people take the plunge. Yes they could gain a small marketshare by doing so, but the benefit would far be outweighed by the cost. Secondly, Shimano fishing operates wholly on its own, when compared to Pure Fishing's brand umbrella. Yes, the performance of the individual is considered, but the umbrella of profi is the driving force behind Pure Fishing. It covers the entire sector, so to speak.