Has something changed?
Yes, many windows have closed, so there is less choice now than before, but there is still plenty of choice. One of the biggest changes is that several of the highest rated girls on this forum seem to have disappeared, which I think has contributed significantly to the perception of a decline in the quality of window girls. Personally, I've always preferred prives, so IMHO, so I feel that the declination of the RLD is a little overstated here, but I also feel the RLD was also somewhat overrated in the first place (this is a very subjective thing).
I also see a lot of folks recommending the privies?
Depends what you want. Service and value for money is generally much better at prives, which is why they tend to get recommendations. On the other hand, prives have less choice and it seems some (many?) people consider the girls less attractive (not me, however). Park 118 seems to be the gold standard for Amsterdam prives, but you're only likely to see up to ten girls working there when you visit. If you're outside Amsterdam, you can get even better value/service than Park 118; I know several places where you can get 60 minutes with GFE, DFK, DATY, CBJ, multiple positions, cum twice, etc. (and sometimes even more) for €100. (Park 118 girls charge extra for DFK and DATY).
There are also bad/rip-off prives in Amsterdam, such as Asmara, that should be avoided.
Is that where the real action is now?
Depends on what you're looking for. Do you value great service or amazing looks more?
Before, there wasn't as much of a selection in the privies as there was in the RLD?
This is still very true.
Also, what about the weed? I've heard tourists can no longer buy weed legally in Amsterdam? Is that true? If so, how do I get around it?
A "Weed Pass" for Dutch residents was considered at one point, but they never actually went through with it, so you can still buy weed as a tourist without any problems. Just make sure you're carrying ID because they always ask for it now.
What are the prices the girls are charging these days?
You can still do a €50 session with a window girl, but many (most?) will try to push for a €100 for a decent experience and I personally find €50 sessions not very interesting.
If you go the prive route, Park 118 is €95 for one hour plus any extras you want (DFK, DATY, BBBJ, anal, etc.). Each extra usually costs between €20 and €50. Having visited two girls there recently, I ended up paying €175 each time in total for one hour with DFK and DATY, but I've heard reports of paying less/more than this depending on the girl.
What do I need to be aware of since I've been away for a while?
If you go to the RLD (especially the Wallen), it's best to stick to the known reputable girls to avoid rip-offs or disappointing service (but then, it sounds like you have plenty of prior experience already with the RLD, so I guess you know this).
If you go to a prive, Park 118 is your best bet, and be sure to avoid Asmara. And be aware of the total cost at Park 118 if you're looking for extras.