I think you should just remove all current recipes for individual tools (there really is no need for those anymore) and the 3-profession combo tools and just replace them all with sets of universal tools.
Example: When you first select your craft, you get a "brittle universal tools", with 30 strength.
Then, along the way, you can upgrade your tools by crafted sets from metal smiths every 10 levels, starting at level 10. These will be "green" with a strenght of 45, and critted purple with a strength of 60. Every 10 levels, just like the current tools, the tool will get slightly better, starting with a 5% increase of crit chance, going all the way to 20% crit chance at level 140. These tools are the easiest to get, the recipes will be free or auto-bestowed, and does not require cooldowns or special materials. These tools will have 5s resource gathering on the green models, 4s on the critted purple models.
Additionally, Guilded Tools are available at SELECT level caps. First one at level 50, then 75, then 100. The next one at level 120, then 140. (A future tool can be added for 160). These are going to be the best crafted tools you can make/get with a strength of 80, starting with a 15% crit chance at level 50, to 25% crit chance at 140 on all professions and 3s resource gathering. These will be teal, require some special ingredients appropriate to the tier, and come with the standard guild cooldown of 6 days and 18 hours.
Finally a bartered tool, ONLY available from Umbar barterers with certain reputation...... but these may have a little "edge". These are universal tools, available in Umbar only, minimum level 150, a strength of 100, and have a 30% crit chance on ANY profession, and 2s resource gathering.
If so inclined, a few bartered tools can also be added to certain expansions, e.g. "Tools of the Riddermark" in Rohan, and "Gondorian Craft Tools" in Minas Tirith.