He did very well on the pitch, no-one is denying that. But he did not have a 'massive influence on the club'. I think only four of his signings played in the first team last year, he brought through almost no youth players. Apart from the league finishes he didn't move the club forward at all. Since he insisted that there was no DoF it is perfectly proper to give him the credit for the things that didn't happen as well as those that did.
And if I wrote "Levy has been here for 13 years, had a massive influence on the club, got us from mid-table to 4th, got us a world-class training facility and a plan for a new stadium" the same people who only look at the league position in judging Harry would find reasons to find all sorts of faults with Levy.
Sandro, Naughton, Walker, Friedel, Kaboul, Adebayor (think it's fair to count him) makes six.
But the playing staff is simply not as effective now as it was under Harry, is it? The fact that we had a very much unnecessary overhaul of the squad after he left (cos of The Project, remember?) is neither Harry's fault nor has it resulted in us reaching The Next Level which, apparently, Harry was holding us back from gloriously attaining.
OK so he liked to sign tried-and-tested players. Point is a) Did it work? and b) Was it sustainable? I think the answers are "Yes" and "Yes". So what if you're not promoting inadequate youth or not signing players in their early 20s if the players you ARE getting in are doing a job and, actually, still have a decent sell-on price (Parker, Defoe, Crouch, etc) and besides they didn't break the bank anyway. So what if you only get two good seasons out of a Parker-like purchase? Better to have two solid seasons from a proven performer than to have "promising" "world-class" talent come from over-seas and have no idea what to do (see all three of our record-breaking, world stars who were signed last summer).
Go through all of Harry's signings and I think you will find that his signings had a higher rate of success than the signings that came immediately before he joined. I expect that time will tell that the same can be said about signings since he left.
Football is not just about "building" and "projects" and wonderful futures where the 15 year-old in the academy goes on to be worth 40m in the future (though is worthless and contributes nothing right now). What is number one priority is the present. What players you have available right now to win games. You want a good future for a football club? Win games. Get success. Then you'll qualify for major tournaments. Then players like VDV will want to join, players like Bale and Modric will not want to leave. The future is based on the present and Harry dealt with that pretty bloody well.