You'll have to provide some evidence on chancellors - personally I thought all three were reasonably competent
I'm an accountant so looking at it solely from a tax point of view.
Brown removing the dividend tax credit was a monumental foul up. He then brought in a 10% tax rate only to scrap it a couple of years later. Then a 10% and ultimately 0% corporation tax rate for small companies which he scrapped a couple of years later. Messed around with retirement relief, business asset taper relief and entreprenneurs relief constantly over the years. Same with capital allowances - up, down, rule changes, etc every sodding year. Brought in tax relief for goodwill and then scrapped it again. Total failure to tackle tax evasion which grew massively on his watch. Botched up the introduction of IR35 which should have stopped tax abuse via personal service companies 20 years ago, yet has only really been tackled in the last 5 years. Closure of loads of local tax offices causing loss of huge numbers of experienced tax inspectors, now replaced by poorly trained and low skilled call centre workers. Selling off our gold reserves and giving advance notice of doing so wasn't a smart move either.
Osborne - pasty tax, child benefit tax, 62% marginal tax rate on GPs and dentists.
Hammond - lazily using draft legislation first drafted 20-30 years ago to reduce the tax relief on buy to let mortgages which contains several anomalies and mistakes which clearly show how old it was. Obviously dusted off from being stored on a shelf and no one thought to proof read it properly to make sure it was up to date and relevant. Presiding over the MTD (making tax digital) fiasco. Lifetime pension tax fiasco.
Us accountants watch the annual Budget with absolute horror as we know the unforeseen consequences of the changes they keep making and then have to change and correct a year or two later. If they really knew what they were doing, they wouldn't make such fundamental foul ups in the first place. Most of their foul ups are blatantly obvious to anyone with any real knowledge/experience of the practicalities of the tax system.