They are not going to care about your law against using ORM tools because of how they cause plan cache bloat; they only care that writing all those stored procedures means many nights of late work if they are going to get their work out the door. And frankly, I think they have every right to be upset if you try and push arbitrary changes on them late in the game, especially if they did the right thing and involved you early on in the process.
"the best is the enemy of the good" - Voltaire
I can appreciate that seems reasonable if your scope of concern is the database; however, as someone who is responsible for delivering entire systems, this line of thinking is troubling. My chief concern is delivering value over the life cycle of the systems we build. In some cases, if not many, the result we are seeking is achievable using software which is not highly tuned in combination with some extra hardware. I'm not advocating sloppy development practices, but the reality, in economies like that found in the US, is that hardware is cheap and people are expensive. Why would I allocate developers to a problem that can be solved by a capital expense? How is the business not better served by assigning a human work that she, barring the awakening of Skynet, is uniquely qualified to perform? It may offend your engineering sensibilities, but my position is that assignment of resources to their best use is the right answer when operating in a commercial setting. After all, keeping the business profitable, not optimal use of the plan cache, is what keeps those paychecks coming to me and the DBAs I work with.