He very well may be a knockout...but if you are buying for resale...he will be 8 after a winter of dressage. Around here, unless he is REALLY cheap, he will not sell. At 8...he needs to be running training level, super fancy (either on the flat or over fences) or an absolute packer to move. Now...he very well may be running training by the end of spring but you are taking more of a gamble.
Now if you are buying for yourself...He might be just fine. But for resale...2007-2009 models are what you want for this time of year...with 2008 being preferred.