Hi Alex,
I have been shooting air pistols at 10 meters since 1971, and over these years I have been fortunate enough to enjoy and own just about all of the match pistols types you will see being used at the world's top air pistol championships and Olympic games - but sadly, owning the best does not make anyone the best shot and what suites one pistol shooter will not suite another.
My own personal collection currently includes several good match air pistols including Steyr Evo 10, LP2, FWB P44, Morini 162ie, and Pardini K12, but I have also owned and enjoyed shooting the Benelli Kite, Walther LP200, Walther LP300XT, Steyr LP1, LP10, LP10e, LP2 Compact, FWB P34, P44 Compact - and just about every CO2 powered and SSP match pistol ever made - and I have enjoyed owning and shooting every one of them - not a dud amongst them - but they are all different !
Every one of the above has its own characteristics that will appeal more to some than others, and every one of them has its own followers and supporters - and they are all more capable than most shooters ability to score a "possible" every time!
I have owned several Morini 162ie match pistols over the years - some have been a lot older than others, and some are of the last few made with the cosmetic facelift (sometimes referred to as the 162ie Mk2) and they have all shot perfectly, and the same as each other.
The Morini 162ie has been one of the air pistol world's best known success stories with what is probably the longest track record of success at International levels and the first choice of many of the world's best male and female pistol shooters - including our own most successful British pistol shooter Mick Gault who shot his with some success!
The fore-runner of your Walther LP400 was the LP300XT and I always found this to be the most forgiving and easy match pistol to shoot. I am a dedicated Walther fan and choose to shoot Walther match rifles at 10 metres, but my preferred choice in pistols has been the Morini 162ie for several years.
Having run several air weapons clubs and been a member of others too since 1971, I have been lucky enough to shoot and own a good choice of the world's best match air pistols and for sure the choice of air pistol is very personal thing - what suites one shooter may not suit another - but none of them are bad.
If you are ever up north you would be welcome to visit our RMTC club and bring your Morini 162ie with you where you can shoot and compare it with several other Morini 162ie match pistols to see if indeed the one that you have bought is not as good as any of the others, but you could also take it to a fellow Morini shooter a little closer to your home and see if they think your particular 162 is inferior to theirs.
Maybe somebody without enough knowledge has been "adjusting" your Morini?
I bought an LP10 once that went off like a canon, had a kick like a mule, and felt capable of taking the bricks out the end of the club range. This did not make me think for one minute that all LP10 pistols had "muzzle flip" - when what had happened was that an amateur "twiddler" had adjusted the pistol's power incorrectly .
Your Morini 162ie is a superb match pistol that in the right hands has surgical precision - if yours feels as bad as you say then it really needs "looking at" by somebody that is qualified to correct it for you.