I do think that HT's should still have the same powers to authorise holidays (or not) as they used to. In theory, they can still authorise for "exceptional circumstances" but our LEA has dictated that a holiday will almost never fall into this category. Therefore the HT has to decline the vast majority of requests.
From a personal point of view however, I will freely admit that my opinion on this has completely changed over the years. I have a large age gap (14 years) between DC1 & DC3 - and 10 years between DC2 & DC3. When DC1 & DC2 were at primary school we did, on occasions, take them out of school for holidays. Not weeks at a time, but certainly for a few days here and there. Both DCs were the type of children to come out of school and tell me they had done "nothing" during the day. We would have daily conversations along the lines of;
Me: Have you had a good day?
DC: Yeah.
Me: What have you done today?
DC: Nothing.
Me: You must have done something! What lessons did you have?
DC: Don't know.
With hindsight (and this may make me sound stupid), I can see that this clouded my opinion of how valuable those 3 or 4 missed school days were to the DCs education. I used to think that they would learn more and get more value out of a holiday as they "weren't doing much in school anyway".
Now, with DC3 at school I have totally changed my views on it. DC3 comes out of school every day full to bursting with every little detail of everything she has done, learnt & seen that day. She is truly like a little sponge and, quite honestly, learns something new every day. I can now see (because DC3 is telling me!) how the English or maths they do one week leads on to the English or maths they do the next week. And probably links in to something else too (history, assembly etc.) Therefore, I now think that taking her out for a week during term time would make her miss so much that I won't be considering it.
Also, now that DC3 is telling us all everything she has done in great detail, her older brothers will say "yes, I remember doing that" etc. etc. So, they were doing these things - just not talking about it!