I bought my 2005 ES 330 in November. My thoughts on your concerns are:
1) "clunking noise" - I have not heard a clunking noise - not even once.
2) problems with the 5-speed transmission - downshift delay - I would not have
known this was an issue if I had not read about it on this forum
3) car does not respond to the gas pedal - same response as above
4) driver seat is uncomfortable - I'm 6'2" 220 LBS and have no problem with comfort
5) car does not corner well - I must drive too slow for this to be an issue
6) poor gas mileage - it's better than the 4 cyl 93 Camry I upgraded from
7) instrument panel gauges not as "snazzy" as those of Camry - baloney (just MHO)
Roy