Hello everyone- I need some advice-

We're remodeling our frequently used guest bathroom and turning a tub/shower combo into shower only with a 3'x5' Kohler cast iron shower pan. This is a 45 year old ranch on a concrete slab and will hopefully be our forever home. We've found a contractor we like and have about 1/2 of the decisions made re: finishes.

Here's the question- A big problem we have with the layout as it is now is that on occasion (3 times in 11 years) we've had problems with the tub draining. The first time our plumber came out, tried every which way including from the adjoining bathroom sink and from the roof to snake it and couldn't get to the clog. He ended up tearing out some of the drywall in the adjoining bathroom to get it unclogged. The last two times my boyfriend has ended up doing the same thing. So it's VERY IMPORTANT to us to have access to things that might break/clog in the future without having to tear down drywall/tile. He also told us early on that when we got to the bathroom remodel to plan on replacing the pipes in the walls because they were very corroded. (Most of the supply lines were replaced right before we bought the house.) All of this has been communicated to the contractor we're planning to use.

So with the remodel I planned to move the shower head to the opposite end which can be accessed from a hall closet. But I noticed in the contract that the contractor is going to use the same drain location. He did mention when we talked about it that he would look at the condition of the drain and possibly have to chip it out to repair if it was corroded.

2 questions:

1) Would the drain location need to be moved to give us a better place to be able to get to it? I guess not, because supply side and drain side don't have anything to do with each other, but if it clogs how can we make sure we don't have to tear anything out to get to it?

2) If the water supply is at one end, will it look weird to have the drain at the opposite end? The Kohler can be ordered with the drain hole at either end or in the middle. I know it's expensive to move things around when you have a concrete slab. But I don't think I've ever seen a drain at the opposite end. I plan on having sliding glass doors if that makes a difference.

I plan to talk to our contractor about it and a few other things at our next meeting but I wanted to know what you all thought.

Thanks for your help- Lisa