What makes for a fun Infection game/map?

I love Infection. It's literally the only reason I play Halo 5 anymore. The things you people are creating are truly amazing and are giving this game life.

But i must confess that recently, the maps and game modes that are coming out just aren't doing it for me. I keep noticing design decisions that are actively making the games less enjoyable. I'm making this thread as a form of constructive criticism, because I want forge creations to ascend even higher than they have already. So first, I will be pointing out things I notice actively make for a less fun game of infection, and then the antithesis of those things that I think work to enhance the game. I would also like you to do the same. I will be using your input to help create a map I'm currently building.
Dislikes:

Problem: Over-sized maps
Solution: Better-scaling and saturation.

I call this the Majora's Mask effect. In Legend of Zelda: Majora's Mask, the map is smaller than Ocarina of Time's, but each area of the game is more saturated with characters and stories and side-quests so it feels more meaningful and vibrant and full of life. I've noticed some of maps have a tendency to mistake quantity for quality when it comes to map-size. I would suggest focusing on making each piece of the map have a purpose and an opportunity for a unique encounter.

Problem: Mismatching, ugly color scheme and out of place aesthetics.
Solution: Keep it simple and have a theme

Maps that aren't easy on the eyes are less fun to play on. Clashing colors and seemingly random decorative pieces can be jarring and distracting. Google a color wheel and colors that go well together to create a seamless atmosphere.

Problem: Wide, open spaces
Solution: Strategically placed and aesthetically pleasing cover and Line-of-sight blockers.

Unless you have a damn good reason for having them, wide open spaces make being a zombie very unpleasant and really just seem kind of lazy. Trees rocks and decorative structures go a long way to making your map feel organic.

Problem: Games where Survivors are always vulnerable and as a result usually don't last very long.
Solution: Damage and speed balancing

If a round of your infection game is taking less than a minute, usually the survivors won't be having much fun. Up until a certain point (I'd say 3 minutes), less game-time means less time for tension to build and less time for exciting encounters. If dying feels cheap and easy as a survivor, I'm not gonna be very enthralled, just agitated.

Also here's some quick things that I think add some flavor to the game:

Maps that encourage teamwork via pathing
Map interactivity with a reasonable amount of switches.
Strong, unique map themes.
Rooms that aren't just big rectangles.
Strategically placed weapons.
Unique zombie traits used effectively.

I think that about covers it. Might add more if I think of any later. Thanks for listening to me (constructively!) complain.

Now it's your turn. What to you makes, breaks, or enhances an infection map/game for you? What design choices really get your adrenaline pumping while you dispatch the undead? Also, just for fun, what's the forged infection map that you love or remember the most?

 

I also have stopped enjoying the linear "Survive" maps. I feel like people have forgotten the basic "dos and don'ts" about level design and are focusing way too much on gimmicks and props and are just hoping it plays well.

Also, can we please start getting more maps and gametypes that play like Halo 3 infection? Without the hovering, sprinting, and boosting that ruins map flow and scaling?