The proposed plan is to drop both the ability to run Rufus 3.x and later on Windows XP...
Instead of subjective preferences and opinions, the decision whether to continue supporting XP within RUFUS could be (also) based on use-case (in addition to whatever (else) Pete might be willing to consider, obviously).
A potential/hypothetical user has a(n old) PC. In one partition, there is Windows XP installed. Other partition(s) contain some Linux distro(s), which might very possibly be the "main" OS in use. XP is there, "just in case", or for some infrequent need.
Once in a while, this hypothetical user likes to try some new Linux distro, or he might want to prepare his USB key with some distro so to show / teach some friends / family members, on their own computers.
This user might (or might not) have the necessary knowledge to do it all under Linux. But hey, there's RUFUS. Let's prepare the USB under the old, rarely used XP, and then back to Linux to the normal daily use of this computer.
The following hypothetical conversation takes place then:
- OK, you showed me some Linux distro. How can I do it myself if I want to try another one in my own system?
- I used RUFUS, under my Windows XP. It will work in your Windows Vista/7/8.x/10 too.
- Are you still using XP?
- Only rarely, as in this case. Now I use Linux mainly.
- Why don't you upgrade to a newer Windows version?
- Because my PC is not new enough. Spending (more) money on a new Windows version (and probably on a new computer) is something I'd rather avoid, or at least postpone; things have been tight during the last few years, and my main OS is Linux nowadays.
- You remind me of another friend. He has some old hardware too. Perhaps he might also want to use RUFUS (in his XP) and try/install Linux in his old system, instead of throwing that (still usable) hardware to the trash.
Why not just use an older version of RUFUS that would still support XP?
Well, because of compatibility between (such hypothetical older version of) RUFUS and (some hypothetical) newer versions of SYSLINUX / GRUB / some other supported boot method / some Linux distro...
Of course, learning how to use a manual procedure, instead of RUFUS, is also possible. And if RUFUS can actually gain some new features that are much desired/appreciated/expected by users, then maybe dropping XP would be justified from user's perspective (too).
This hypothetical use-case – whether a common one or not for RUFUS' users, I wouldn't know – might not change any opinions or decisions in this topic about RUFUS under XP, but I thought it _might_ show some slightly-less-subjective perspective.