Hi there, How're you?
1st of all I agree with you...HARRIERS are GREAT

I'm part of a VAir Force (
www.rafvirtual.org), I'm in the 801 RN Sqn, wich flyes the....Sea Harriers:D My Sqn OC is....Adam Preece from AP designs hehe, so I may say I have some good knoledge of what's going on...
I must say that this flight model is as good as adam could make it. Yes you're right it does accelerate a bit too fast, but don't be mistaken, harriers are VERY powerfull a/c!! The problem is that FS9 and all microsoft sims before can't simulate vectorial thrust!!
Adam tryed to resolve this when he was converting the sea harrier to fs9, I went all over internet forums of designers and air file experts, and so did adam, but there is no solution!! A harrier hoovers when the nozzles are full down. it can hoover, go backwards rotate, etc. In FS this is impossible because the air file doesn't allow you to have multiple angles of thrust!
I mean: you put the angle of thrust in the air file and that's it! it won't change!! So, to try to make it as near as possible to hoover, what one does is put extremely strong flaps in the plane! that way you'l have huge lift at extremely low speeds! The lowest controlable speed I get in this plane is about 6-9 kts! that's as low as adam could make it, and believe me it's very good!!
The problem with this solution is that:
1. obviously, you can't really hoover (unless there is some wind...).
2. The behaviour of the plane when in normal flight get's affected, and it doesn't behave as real as it should, but since this plane unique feature is hovering, adam decided to balance both flying modes, and try to get an equilibrium between them...
In the end, it's a very fun plane to fly, it allows you to do stuff that other fighters can't dream of, yes, it's a bit overpowered but not too much believe me

And don't forget that it's not the easiest plane to fly, it requires you to get used to it's reaction, especially when slowing down for touch down, and when using flaps!!
sorry for the long post, hope to have helped...