Well, I'm going off Orange then...
I'm fed-up with operators "improving" their handsets with ghastly colour-schemes and flaky firmwares.
The main problem with it (apart from the horrendous lack of taste with colour schemes and occasional disablement of functionality (VoIP anyone?)) is that operator customised firmwares are often not updated by the network operators for ages or at all, after all, they've sold the phone now, so why is it in their interests to make it reliable, they'll just sell another one on a different brand in 18months time, it'll cost money and most users aren't savvy enough to upgrade the firmware (present company accepted) anyway.
The first thing I try and do with Orange phones is de-brand them to remove the stupid menu and get an up-to-date generic firmware, luckily it's relatively trivial to do on the Nokia N-Series phones, as is removing the logos they insist on graffitiing the phones with. It's just as bad with Vodafone and their "Live" software and horrible red colour schemes they tar their phones with.
The best thing to do would be to force operators to separate the phone service from the phones, remove the fee that people pay in their contracts for the phones and reduce contracts to 1 month max, if someone wants a new phone, fine, they can pay for it, phone shops could offer incremental payment schemes, so people don't have to fork out a whole bundle of cash, or if people want to pay for a phone outright they can as well, or be able to be affordable with a cheap contract and the same phone (and no the sim-only deals operators offer now aren't competitive, if you take a sim-only contract with X mins and Y texts, and compare it to a with-phone contract of the same spec on the same provider, often if you account for the cost of the phone a lot of operators are creaming more profit from the sim-only deals!).
a) Network operators would have NO say as to what people have on their phones.
b) There would only be one firmware, which it would be in the interests of the phone manufacturer to keep up to date and reliable as otherwise people won't buy their phones anymore.
c) It would make the market FAR more competitive, people could just switch at the end of the month if the operator didn't provide efficient and cost effective service.
d) If there was a phone someone HAD to have, they could switch easily. :)
Well, that went a bit off-track but I think I've had my rant about all that's wrong with the UK mobile phone industry. :)
*Pickpocket because Mobile Phone Networks are fleecing us daily... :)