the short and simple answer is no. as long as everything else is the same if you are comparing it on 2 identical tvs 1 720p and 1 1080p the have identical or near identical specs. Every 1080p tv I know of also displays 480i/p 720i/p and 1080i/p. The disc that you are playing is a 720p disc so the will only produce the 720p image so the will look the same on either tv
Never heard of 720i. The term in itself however, is erroneous and is usually a typo. The user of the term is almost certainly talking about 720p as there is no broadcast standard that allows for 720 interlaced lines in a video at any frame rate, including PAL or NTSC.
I had an issue with playing a 720p online only game on the PS3. I bought a Sony KDL52s5100. Socom:Confrontation is 720p. I had previously played it on a 1080i only tv and a SDTV. When I played it in 720p it had a lag to it. I found myself over correcting when I moved my character and it made me into a garbage player. I used the setting on the PS3 to force it into 1080p and the delay I was seeing was eliminated.