Is it OK to ask my host for an externally organized stay which hotel is being booked? I will be spending 2 weeks in China later this year, to visit a university and talk to the various research groups. The host university will be paying all my expenses.

My contact person at the host university has asked me if I would like for him to make hotel reservations for me or if I would like to do it myself.

Ideally I would like for him to make reservations, as he knows his own city. But am I "allowed" to ask to see the hotel first, before he makes reservations for me? Or is that considered impolite and rude as they are paying for me?
Given that it's in China (and I'm assuming you're not Chinese), I would let the host do it for three reasons:


It's important to be gracious to the host. This is a general rule in most cultures, but particularly in East Asian ones. Letting your host be a good host is part of this. Trust your host's judgement here.
My experience with Chinese hotels from Shanghai to Xinjiang is that there is minimal to negative correlation of the quality of the hotel to the website or the official star rating.  It is highly doubtful that you could ascertain anything superior from afar than what the local person would know. 
Logistics. The host may want to put all of the people in a particular hotel (or spread them between a particular few) because of logistical reasons: geography and   they have only one van to pick everyone up, etc. etc. 


I would let your Chinese hosts handle everything. If you have particular needs (room must face towards the south; hotel restaurant must have halal food; etc.) then let them know. Otherwise, let your host be your host.