For my taste:

- more consistent and better physics - I can give numerous examples, but just latest from my son's playthrough - standing in shadow during the day in Gerudo desert with ice block in your hand and waiting for the night to come, knowing it won't melt, while you're waiting the whole day, is just bad design (this is how he solved today Pokki's quest, going around all enemies).
- more enemies, suited to region and with different resistances to certain types of damage
- more weapons with defined type of damage
- no endless slate powers, especially bombs are ridiculously overused - "magic" needs meter/"mana" like in previous games
- weapon and shield wear and tear is fine, in fact armor should have it as well - it's just they all need some sort of meter to show its condition, as well as blacksmiths to repair/fix them
- underground locations - every time I ran into some destructible rock formation I was hoping it will be entrance to some underground dungeon...no such luck...which brings me to:
- classic 3D Zelda dungeons sprinkled with classic RPG dungeons...game really needs them...no, Divine beasts are not good replacements...they are fine, but they are too easy, too short, and too few...which leads to:
- no shrines...they are really poor replacement for dungeons - there's nothing more boring than solving neat environmental puzzle and getting yet another orb (and potentially some breakable weapon/shield)...this lead to:
- proper rewards should be really high on their to do list - it's about time that LoZ gets rings and amulets - jewelry in Gerudo Town was step in the right direction, it just needs to be rings and amulets, so that they do not take up armor slots
- no Korok seeds - most of those "puzzles" are boringly repetitive and it's really silly mechanism to enhance your inventory space...this leads to:
- inventory really needs fixing - sorting is terrible and ingredients are not marked with what their special properties are...and limited weapon/shield space makes no sense whatsoever the way it's implemented; also pausing game while going through inventory and healing yourself is really, really bad design
- no towers - I honestly see no purpose in them, other then getting a map - and I'd rather that maps of different qualities are sold at the shops or with NPCs, in addition to being auto generated as you explore (in latter case, names of locations would appear on map only if you acquired that knowledge in some way)
- climbing - this is one of my pet peeves with a game - while I like that there is climbing in game, its implementation, for me, breaks the game in so many ways - Zelda is not RPG, so attributes, skills and other modifiers are not to be expected, but something like encumbrance should be a thing - wear heavy plate armor and have ton of loot and see how good you are at free-climbing 90 degree (or even more, which is even more ridiculous in BotW) vertical cliff - this would at least make current very basic hearts/stamina upgrade path somewhat more interesting and make different playstyles necessary, depending on personal preference
- better side quests - while there was enough of them, most of them are quite simple and forgettable...it is, after all, post TW3 era.

The point is that you get a high vantage point from which to spot and mark out landmarks like shrines and camps and stables for future reference, instead of the Ubisoft approach where climbing a tower just fills in all the landmarks on the map for you.

The towers also give a greater sense of progression than just buying maps as they give you a goal you can see from afar to strive for and conquer.

Yeah, they are definitely better than Ubi crap - although they are directly influenced by them.
You can get vantage point from anywhere high enough, you don't really need towers for that...IMO, towers in BotW are just forcing you to go to them for map, since there's no way acquiring them any other way.

I like map buying (preferably of different qualities, thus different prices) + compass approach the most (like in some older games) - they don't even show you where you are on the map, you actually need to take in your surroundings and learn landmarks...but I guess that would be just a bit too much for mass market game in this day and age.

Yeah I suspect the mass market would balk at that somewhat. 

BOTW does push a little in that direction by making the maps show only topography and making the player fill in the landmarks manually. You don't strictly need a tower for this as you can do it from, say, a mountaintop, but I feel like having the towers still fills an important role not just in getting maps but also in that they're something you can see from a distance and pick out as a goal to work towards. 

I for one got immense satisfaction from setting my sights on a distant tower, journeying across the unmapped wilderness to reach it, fighting through whatever challenge is put in place around it, and being rewarded by lighting up a big slice of the map. So in that regard I think that they're crucial to giving the player a sense of structure and accomplishment, so that the world doesn't feel aimless.

Add an online mode. Game will sell another 20 million alone based on that.

Hm, I don't know, honestly, I really went to towers mostly just for the map - I tend not to like any handholding, but I do need some sort of map...at least in bigger worlds such as BotW. However, I don't find BotW maps particularly good, IMO they show too much for my liking.

While we're at maps, ability to put custom marker would be nice, along with text as reminder (that you can read when you hover over it) - something that some old games did as well.

Guess it's just a matter of taste; in an open world game I need clear goals/objectives to strive for, stuff to set my sights on. The towers gave me that.

Great to see a fellow Arlo fan. He makes quality content.

I actually really loved the towers. Filling in a blank map just satisfies me so the first thing I did once I was done with the Great Plateau was to run directly to every single tower and complete it without deviation. Only once I had all those did I start to adventure like normal. Of course, that's a personal quirk as I did something similar with all of the map squares of the Great Sea back in Wind Walker.

Yeha, I guess it really boils down to personal peference . I always tend to like the games that don't give map at all, so you have to automap while you're exploring until you potentially get somewhere that you can buy/obtain map. And as I said previously, even then I prefer that there's no GPS included, so only way for you to know where you are is via landmarks and compass. But that's really crucial game design desicion, so those worlds need to be made with lot of care for navigation and orientation.

Hm ... if only there was some kind of natural formation you could use to get to high vantage points ... something maybe you could climb on .... then we wouldn't need towers but clearly nothing like that exists so towers it is then.