First, about me. I'm probably one of your loyaller users. I've been using Firefox since it was called 'Mozilla'. I remember Phoenix and Firebird, and I've used every major version of Firefox since the name began. I have Explorer, Chrome, Safari and Opera all installed, but Firefox is the one I use daily.
I don't mind the ads. I recognise desperation when I see it, and I sympathise. I think a lot of the interface changes are pointless, but I'll live with them if that's what you enjoy doing.
But I wish you would get around to doing something useful with this hilarious release cycle of yours.
What we need isn't a more seamless or faster browsing experience; what we need is control over the browsing process.
Let's consider, for a moment, the scourge of auto-playing videos. These come in two flavours: the ones that start playing as soon as you open the page, and those that give you a n-second countdown to click a button to stop them. On a slow or unresponsive system, such as mine often becomes when I've got a few apps open, there's no difference between the two - either way, as soon as I switch to the tab, I'm condemned to complete loss of control over my computer for 30 seconds while poor little Windows tries to decide what to do next.
There's no reason for this. Give me a 'Play' button, and let me decide when (or whether) to click it. If you can configure Firefox - or allow me to configure it - so that it will never on any site, ever, no not even then or there, play a video without waiting for me to click on a button clearly labelled with a right-pointing arrow head of some sort... that would be a victory. I realise this is technically not as simple as I'm describing it, but that's why you employ clever people.
(In this context I would draw your attention to this well-reported study, which showed (indirectly) that people are much less likely to click on video ads than on regular, static ads.)
Another scourge you could control? Sites that insist on refreshing themselves at stupid intervals, where "stupid" is defined as "anything less than a minimum that I, the user should be able to configure in my browser from a simple menu setting". They eat my bandwidth and slow down my machine, all so that some media wankers with an inflated sense of their own importance can avoid the terrible stigma of their site appearing to be three minutes out of date.
And auto-redirecting. I know there are many good reasons for this, but there are also many bad ones. It would be nice to have a browser option to disable it, so that when I type in or click on a URL, I would have the option to see the content hosted at that URL and no other.
Remember pop-up and pop-under ads? For a brief time in the early 2000s they seemed to be the unstoppable scourge. Now? They haven't bothered me for years, in part thanks to you. You can do it again.