Mapping and Sextants, Questions from a Designer's Point of View

I think that that I would agree with that fact that sextant mechanics need to be reworked. Particularly Sextant blocking as it also "blocks" players from running other maps that might fall under any of the maps without the possibility of ruining all the work that was put in setting the blocking up.

When it comes to the mods of sextants, I think that the trimming of the mods that can be rolled could definitely feel better. However I don't think that its necessary to do so. In a experience filled with RNG and variance, I believe that its important to different challenges be set forth by a map augmentation system. I would suggest that there be additional variety of sextant mods, things like Area contains additional Monsters that are hyper aggressive(much larger agro range) or Area contains additional Towering Giants that are guarding coffers(Yellow monsters that are permanently influenced by a 4x Massive Shrine). Adding addition mods that feel rewarding could also accomplish similar rewarding experiences without removing the RNG that provides variety since you would have a smaller chance of rolling bad mods.

I definitely think that having sextants only affect maps that directly connect to where they are placed, would reduce visual clutter as well as tone down sextant blocking. Another change I might suggest would be making sextants less static. Similarly to how Zana map mods or league stones can effect maps regardless of what map actually is placed into the map device to be run. Maybe sextants actually become a movable element that you can place on your atlas that allows positioning to still play a factor similarly to how parallel rulers and dividing calipers were used as active navigational elements on a map .

I would agree with you if a player just applies a single sextant at a time. However,
the wonderful intricacy of the sextant system allows you to have multiple sextants buffs apply to a single map due to the overlapping nature of the red circles of influences applied by each sextant. Due to the nature of rng, there will of course be some mods of sextants that don't actually have a profitable return such as "Players deal 100% increased Damage while stationary" as you mentioned. This would make sextants a lot less profitable if you weren't able to manipulate the RNG through the mechanic of sextant blocking. Take another look at this image again This is a fully sextanted setup for Shaped Vault and Shaped Channel. You may notice that there are quite a few things going on here. I'll list them.

First: There are about 34 to 36 sextanted maps on the left half of the atlas. Why is that you might ask, if this setup is to aimed to ONLY provide sextant bonuses to Shaped Channel and predominately Shaped Vault. This is because once you place a sextant on the map, whatever roll that sextant got can not be rolled by another sextant withing a similar area of the atlas. This allows us to do something called sextant blocking. Where we roll all the bad mods, some of which you mentioned onto the maps surround but not influencing Shaped Vault and Shaped Channel. This then means we are significantly more likely to roll a juicy mod we want on to the sextants that actually influence the map we want to run. In the end, by stacking addition monsters mods we can gain over 200-300+ additional monsters in a single map as well as some Increased Item Quantity. Which will easily guarantee we can pull in over easily conservatively 30-40+ on chaos a single map without utilizing any other mechanics like party magic find and Increased Quantity Culling Characters. The reason our haul can be so high is because since Shaped Vault is a Tier 14 map, it will drop additional Tier 14 maps. In our case it can ONLY drop Shaped Vault because that is the only Tier 14 map we have completed on the atlas. Meaning not only can we easily sustain the map pool but also sell additional maps that drop for 10-12c each.

Second: Notice how wide of a range that the sextant influence covers. This means that to your early point of not thinking it disincentives running other maps, if we can't running any of the 48 maps that are under the influence of sextants without potentially ruining the expensive sextant blocking that we painstakingly set up.

Third: Notice there are no completed Tier 14 maps on the image this is because if we running another other Tier 14 map other than Shaped Vault we ruin our loot table for map drops by allowing maps that aren't set up to be run through sextants appear. Meaning we have an nearly 50% opportunity loss if we complete a single additional Tier 14 map, much more than one. This means we are now once again limiting what maps we can run if we already spent the time and money investing in sextants.

My last thought is that, you are right I should have had more detail on "The advantage of using sextants is so high, not using it is imperatively crippling." If it was simply losing an advantage then I would agree with you. However the fact that sextants exist as a mechanic in PoE means that they have to balance around it.

Let me use the analogy you presented: "The advantage of wearing a helmet is so high, not wearing one is imperatively crippling". This would be fine if sextants have a purely additive influence on the game. However, that's not the case. Sextants provide a problematic balancing situation.

Imagine this: "Because player find the benefits of wearing helmets so high, we as GGG have decided that in order to maintain the balance of the economy and power of players in Path of Exile, we have made it so that all players will now have an additional base -20% all elemental resists to balance the game. This will bring the effect of helmets back in an acceptable range. Have fun!"

This is what actually has happened. GGG actually nerfed the base density of a considerable amount of maps to counter balance the power of sextants. This is why when you run a map like strand for example it seems almost abandoned as there are almost no monsters in the map. Here is a url where you can read more about the design decisions. https://www.reddit.com/r/pathofexile/comments/6tdjla/wheres_the_official_source_for_map_nerfs_in_30/