Now you just need another switch and router but in a lot of instances, that is overkill, especially if you have other sites for DR. You do have plenty of room for expansion though, now you can lease a couple of U's to some of the other witnesses, or drop some of your EOS gear in there as well.
A trick I learned, completely configure everything, routers, switches, servers, storage, before going to the remote location. Much of the time you can get it all done, then just change the external on the router and be ready to go. (I know easier said than done.)
When you bring the witness back online about how long does it take to sync up? (just gathering intel and weighing some options.) I have a datacenter 2 miles from my house, I have some concerns about it. Mainly, they have just one pipe in and it's on the XO network, but they are working on getting two more from different regions. They will offer a 99.99% SLA but in a previous career, I received several days of free service.
I'm relatively new but from my perspective, you have a business to run. Unfortunately, politics do play a part in most businesses, but you have to do what is best for you and your business, whether others understand that or not. Investing time and resources in multiple blockchains is smart. If you were buying stock in a company, would anyone expect you to just buy stock in one company? No, and I don't really see a difference here. In my opinion, you are just diversifying your business to reduce risks. Just ask the people who are concerned about it, if the only cryptocurrency they own is Steem or SBD.