With Innova putting more and more emphasis on new discs instead of focusing on their staple, i.e. the Roc, I think the market is prime for a new mid. I know I'm down to my last two DX Rocs with the straight up and down rim and all I see on the shelf is the slightly plus molded versions, when these two are gone I'll be in the market for a new workhorse mid.
As with the lessons you learned from the putters there will likely be lessons learned from a mid that you can apply to driver. I imagine the principle of learning to manufacture discs isn't all that different from the principle of learning to throw them. Start with a slow predicable putter, I haven't thrown the Scale or the Serpent but from what I've read it sounds as though you've checked that off. Now move to the mid-range discs and then the drivers.
Don't jump ahead is my advice.
As for the lid, the same debate is running through the MVP threads as well and I'll be honest, I love throwing lids, all of them, they are fun to throw and easy to learn, they require more finesse and nothing sits and sticks like lids but they have a limited following and given how long the stacks of Birdies and Polecats sit on my local retailers shelf I can't imagine Innova is producing them at much of a profit which for a business has to be the goal.
When you've got enough market share that RDG can support itself and you then give the fans that grew your business a lid if they want one, for now I think a lid would be a step backwards and a driver skipping a step forward.