The main issue is this: You've got a top producer making demands that you're unsure of the ROI on fulfilling. You may have some prospectors who are trying to subvert your experienced talent. You may need to look at a bigger picture.
Resolution: It doesn't matter what your top producer is asking when you compare it to other 'visitor statistics'. Visitor stats have nothing to do with customer/user stats, Period. Trust me on this one. Just compare apples to apples. Someone is trying to delude you by giving you an inaccurate comparison value and asking you to support it. You should consider whether that person belongs in your company.
What you want is your site working for your paying customers, and all of them, 100%. If you get an issue with a new paying customer/user, resolve it immediately! Issues with non-paying users are trivial. Your visitors will invariably comprise a very low conversion rate when compared with your sales attrition stats, so the natural course is to develop fixes for the paying customers and let the visitors recieve the trickle-down benefits as they are developed, thus increasing your visitor conversion rate. That way you capitalize on new market penetration immediately, and you look more professional in the process. Your sales leader will always tell you where your best development efforts will be made profitable or they won't be the sales leader for very long.
Plainly, the way to go is to retain new customers by resolving each and every issue with your top producer. The leader is the one you want to watch for issues with your site, not the sales stragglers and finger pointers.
Put it another way: Your top producer is looking to penetrate a new market with special needs which you will have to code for and update on a regular basis. Assuming you've put the proper development protocols in place, you'll have the bug fixes done in 10% of the time it would take you otherwise and far in advance of your competition. Your sales leader is the leader because that person understands that it's a win-win situation all around. This person seems to be doing it right.
If you were to go with the law of averages/slowest mind wins scenario, the majority of your underproducing sales staff would align against your best talent in order to make themselves look good without expending any more effort than it takes to badmouth someone. Think about it. Someone asks you to give them a sharper machete in order to pave the way for everyone else in the safari and you're the one holding the whetstone, what do you do? You sharpen the leaders' knife and follow. Those grumbling behind you don't know where to go next, but they'll criticize anyone in charge because they're not competent enough to lead. It's a basic jealousy trick. Don't fall for it.
Best of luck to you. I hope you don't consider free advice worthless. I have seen companies succeed and fail by these principles, or their lack of adherance to them.