So, me and my buddies had a great deal of stuff saved up for 1.6 in the way of gold keys, and writ boxes. I will here post the data complied on the turn in. I will also post my results from the last week of gathering my 8 toons worth of now depleted level 3 hirelings.

I'll do gold keys first. A special thanks to Hypertoxic, loli, Stevo, Vaun, and everyone else who's data mad it into this number.
Out of 298 total gold keys 94 sets of monster shoulders were acquired.
This rate 31.5% can be reasonably said to probably represent a drop rate of 1/3rd which is about 2x the previous rate as stated in the patch notes. The question of whether or not it is worth doing dailies should be visited by the player though as the primary advantage to monster sets over alternatives in 1.5 was their ability to bypass the caps on spell power, weapon power, and regen to provide meaningful dps or heals bonuses. With removal of caps their relative advantage is less if any. My feeling is that gold keys are probably no longer worth pursuing unless your undaunted rank is not fully leveled up and then really only for the undaunted rank. I do not feel the loot justifies the effort to acquire it especially given the low XP / hour in vet dungeons and the relative power of champion points.

Next we will visit crafting writs which, as I think everyone knows, were a huge waste of time in 1.5 following the great nirncrux nerf. Only Alchemy writs remained interesting. Now however gold mats can drop in writ boxes and the nirncrux drop rate has supposedly been buffed. I had a bunch saved so we'll see what we get.
11 Blacksmith Craits -> 4 surveys -> 1 nirncrux -> 4 gold mats not counting refining
15 Clothier Sachels -> 1 surveys -> 1 nirncrux -> 3 gold mats not counting refining
11 Woodworker Craits -> 2 surveys -> 1 nirncrux -> 1 gold mats not counting refining
7 Provisioner Packs -> 8 green recipies -> 3 blue recipies -> 1 purple recipe

Further compressing this data would indicate a 9% chance of a nirncrux and a 24% chance of a legendary temper though this assumes the drop is constant between all types of writs and it does appear that it may be lower for clothing. Given that a writ takes maybe 600g in materials and yields on average 1.6k value these are now technically worth doing though the return of gold / time spent is very low. You would be better off vending the stacks of mats and just gold grinding or thieving if you are poor. As usual ZOS is rewarding activities they claim they want you to do very poorly. Depending on your recipe state provisioner writs may be worth while though as they are very cheap to do and drop recipes of a variety of levels now. They will help you fill in missing things.

Lastly I will come to my formally beloved hirelings. For them I logged in every day a few times a day because they were very rewarding indeed. I have level 3 hirelings in all crafts (I only have 7 provisioner hirelings) on all 8 toons. The totals below exclude provisioning as I did not keep data on it. Provisioner hirelings now return common ingredients in packs of 20 and purple ones in packs of 5. If you want ingredients they are worthwhile though from an income standpoint I have never delved deeply enough into the cook profession to know what income this equates to.

Formally, my 8 blacksmithing + clothing + woodworking + enchanting hirelings yielded 3.5 golden mats per pick up on average so around 7 per day because of the 2 pick ups. I never really kept track of any of the other color stuff but it was a lot. Post 1.6 I have picked up the hirelings 10 times and received:
9 gold mats (6 dreague wax, 2 rosin, 1 tempering alloy, 0 Kuta)
87 purple mats of various stripes of which only 2 were Rekuta though
146 blue mats
58 green mats

So, my impression is that gold mat drop rates have been decreased about 75% from previous levels with perhaps Kuta being hit the hardest and dreague wax the least. Purple mats may or may not have been changed at all as they were plentyfull before and are still so. As usual, ZOS has used the big boy nerf hammer in their endeavors perhaps following the logic that in lieu of new content we can all just work much harder to get stuff from the old content. Perhaps they think hirelings need not be the carrot to log in any more as we have 1 CP of enlightenment. Perhaps they are unhappy with the relative lack of botters coming the hillsides for mats to refine lately. Who knows. I don't think hireling drop rates were an issue on the top of anybodies list of complaints but there you go.

In any case, the questions you have to ask yourself are whether or not hirelings are worth creating (takes about 15 hours play time and around 80k worth of junk or mats to make a full rock and roll 4 profession hireling toon) if you have not done so and whether or not they are worth picking up if you have them as it takes about 15 min to do so and sort out the resulting mats. It takes longer if you then list mats for sale as a gold source. Really, I don't know what your gold or play time situation is so I can't answer any of this for you. I am personally less enthused as evidenced by the only 10 collections in 7 days. I never would have been so lax before but a few days into 1.6 I found myself just de-prioritizing pick ups. Perhaps it is just because I have too much gold and to many stacks of mats though. I had become lax with my listings even before hirelings were nerfed. For a newer player hirelings will still certainly keep you in purple gear though the price of purple mats is just not all that high on the market anyway and hirelings seem poorly suited for golden at this time. Certainly the return on investment is much lower now and even the time it takes to pick up hirelings might be approached in ROI buy simply steeling stuff in town as I hear 10k per hour is not unusual even for a novice.

So, there you go, some data on returns on investment for several in-game professions and activities. My personal thoughts are that none of them are particularly extrinsically rewarding at this time.