I'm in the middle of the my first game with the Death & Taxes Mod. I like it. Most of my tricks still work, they just need to be tweaked.
The new Trigger Modifiers are incredibly fun and really compliment my non-blobby, strategic-and-valuable-provinces-only playing style: The Strait of Suez, Gibraltar, Dover, and The Cape all now give minor bonuses (as they should), making their acquisition very satisfying. It really creates the impression that you're slowly gaining control of vital nodes in the arteries of world trade. There's something wrong with Sound Toll, though. The events aren't firing properly.
There's a new Administrative Merchant Republic government type which allows you to actually upgrade your regular merchant republic at Gov Level 22. Unfortunately, the Administrative Merchant Republic apparently hasn't been coded into the events and decisions associated with Merchant Republics, rendering this new government type functional only in the most basic way (trade leagues stay intact).
Trade Stations built in your league members now pay dividends through an event that fires every 5 years, with the event depending on how many trade stations have been built. However, it requires the Merchant Adventuring NI, and even though its been buffed, I'm debating if its worth getting. I'm impressed with the elaborateness, though.
CoTs now require 800 D to be built, and random CoTs that start with low value now usually collapse in a couple months via a special event. CoTs also now disappear if Stagnation reaches level 20 (instead of Level 50 in Vanilla). This means the CoTs in Lisboa, Novgorod, Ile de France, Constantinople, and others, have all disappeared in the course of a few decades with very little intervention from me as the player.
The "Weaken Rival League" spy option unique to merchant republics is now much less useful since its limited only to targetting other merchant republics, which I think was a wrong move on the modders part.
The Minimum Centralization for Merchant Republics has been lowered from 0 to -2, making Revolt Risk less of an issue.
Overall, trade is now less valuable because most base prices have been halved. I've been particularly shocked at the reduction in the base value for Cloth, which now renders them not much better than Fish.
The events associated with the New World natives are pretty cool.
Finally, the coolest thing of all: I get to play as Florence.
It starts as an OPM Noble Republic (which is easy to convert to MR) on one of the most valuable provinces in the game. I actually believe Florence spent a fair amount of its history as a merchant republic (look up the Florin, or Florentine banking), so its entirely plausable.