Yes. This is the issue with the Hotel Du Louvre.... not its proximity to the Louvre or to other famous sites. The Park Hyatt more than makes up for the extra few minutes you might have to walk and I've made the walk more times than I can count... IMHO both are so well located that it is ridiculous to even worry about the location of either. Neither location is a problem. The PH will be, with little doubt, a fantastic experience. The Hotel du Louvre will likely be fine but not who knows as it's been a Hyatt for so short of time. The fact that is going to be renovated should speak volumes.

Quite frankly if I were in your place uniquetraveler, I'd stay at the PH for 5 nights after spending the first night somewhere else...anywhere else for the first night and then the last five nights at the PH... there are plenty of very nice non-chain options in Paris that won't be outrageously expensive. If your departure from Paris involves an early flight, just spend the 6th night at an airpot hotel that you can transfer to later in the evening after spending the full day in paris. The hassle will quickly be forgotten after your time at the PH.