I've only done two WCs (gave up on an Orthodox one faith that would've easily been WC but I wouldn't be able to convert colonial nations in time), I regularly reach the mid-to-late 1600s in various stages of blobbiness and these are my observations:
1. Mana is no longer as much of an issue. You get so much more (+5 advisors, cheaper advisors, +mana from estates, etc, etc), plus you can disinherit/abdicate if your heir or ruler sucks.
2. 1444-1610 is primarily meant to give you a strong foundation for massive absolutism conquest. Of course you can't be an OPM by 1600 and have an easy WC, but you conquer way, way, way more land with absolutism than without.
3. AE became more of a bottleneck as more provinces, development, and tags were added. This was slightly alleviated in the previous patch, but you really want to expand in multiple directions using reconquest wars or diplo vassalization to reduce AE gain.
3b. Diplo vassalization is so strong right now. With the introduction of monuments, you can get so much dip rep not even counting ideas.
The easiest WC option is probably Mughals, followed by Ottomans. I am not sure which are the best contenders for the non-Muslim options, but they are probably less expansive/immediately powerful (Holy Roman Empire vassal swarm reform excluded).
Monuments:
There is one in Granada that gives administrative efficiancy (nerfed to 5% out of its original 15). Rhodos has 15% warscore against different religions, as does Mecca (only available for Muslims). These three are the ultimate blob-mode monuments, but Paris (15% better relations over time) and Bangkok (-10% aggressive expansions) just make it a lot easier not getting into tedious coalition wars. In addition, I always try to get somewhere around 50-80% advisor cost reduction from monuments; it is a bonus that is sprinkled all across the map for a lot of different monuments. I pretty much always try to get Amsterdam as well for goods produced and burger loyalty equilibrium.
Plan ahead which monuments you want and which of them requires accepted culture. I tend to only accept cultures required to enable monuments (English, Dutch, Egyptian, Syrian, etc).