I wanted to give you my perspective on your first question having been a part of M&S rework, and being involved early on with the high level design and some granular details of this project. I don't like using the word 'rework' sparingly but we'll use it for now :P
The bulk of what made M&S such a huge project was not the core skilling flow but rather every other thing that plugged in to both skills which had to be reworked. Each and every single one of these (invention tools/perks, potions, drop tables for monsters/rewards across the game, miscellaneous rewards such as Varrock armour, scrimshaws, quests, summoning familiars, worn gear and so on) required at the very least design work, dev work, and QA. Other things may have also required artists and audio for example. All of this bloated the time needed for the project.
From our learnings, the approach we've had since then is to do smaller, more contained "reworks" or rebalances that we can try and fit into projects on our road map or schedule somewhere, whereby we could do the full rework over time but in segments. One recent example of this is the Divination "refresh" Mod Shogun was also a part of. It's easier to justify and deliver reworks - or steps toward a full rework - in this manner.
To do that we have to be very critical of what we allow in that contained design or otherwise we start to bloat scope again or sacrifice another part of the update, or another update altogether. RuneScape's huge and has a lot of content over its 20+ years of life, there's a lot of interconnected content, and we're a super passionate bunch so it's hard to say when we should stop. Woodcutting is connected in ways to Fletching, Firemaking, and Construction. It also has it's own variety of buffs and bonuses we need to be aware of. The question of "how far do we go?" was constant because it's not obvious when to stop. How far do we go getting involved with firemaking, fletching, construction? How far do we go changing misc content/buffs/skill boosts? How far do we go changing quests or other content? Does it all make sense or is it broken if we release it with X, Y, and Z? The WC changes you see displayed here in this project are all that we decided would 1. fit in scope and 2. actually make sense and work being released without a full scale rework.
Another challenge we had early on with this project's scope was that we needed to release new content in the same update too, not just the WC "rework" stuff. It needed to be tied into the fort and progress the season story in some way - and that's why we have an update to the fort in this update. We had to play a big game of balancing the scales so that we could appropriately balance on one hand - a new update that delivers some new content for players to play and advance the season, and on the other hand - some core WC changes that could effectively make the skill better as well as giving us a better platform to do any future rebalances/reworks to WC content (or FM/construction/Fletching etc.)
TL;DR - It's easier to justify smaller and contained reworks for a skill, in segments, inside projects over time that can lead to eventual full scale reworks rather than outright doing a full rework all at once.
Hopefully that gives some insight in to it all, and well done to the core team on this project - they've done a wonderful job!