In order to make any real noticeable difference for time issues such as animals dying too soon and too many micromanagement tasks popping up - particularly in larger zoos -, the time would need to be reduced drastically.
Would you really like to spend a month of your playing time (or much longer, depending on your actual daily playing time) before you get to see an elephant baby? Or for your turtoise babies to grow up so you can finally sell or release them to empty their overcrowded habitat? Aspects like those make me wonder how much the slow mode would end up being actually used... and you couldn’t really speed the game up whenever you like without getting bombarded with messages again. I personally wouldn’t use it, even though keeping everything runnig smoothly can get quite hectic every now and then, I am not denying that. But I consider this part of the challenge. If I want a relaxed play, I play Sandbox.
A lot of people asking for the slower mode don’t want to pause the game all the time. But what’s the problem with that? It’s not like you can deal with other stuff or watching your baby animals while sorting out a fighting issue due to maturing offspring. Take care of one issue at the time in pause without stressing about it, and then return to where you were before without missing a thing. Why is that a problem? Even with a slow mode, there will be times where several events requiring your attention will happen simultaneously, particularly once your zoo reaches a certain size.
What many don’t seem to consider is that the existing speed modes are simply everything multiplied by a certain factor. Everything just happens faster, including the animation. The time relation between every single aspect of the game remains constant.
Reducing the normal speed without reducing the animation speed, on the other hand, would be no easy task as everything that takes time and animation would need to be balanced out again, with the very high possibility of creating new bugs or imbalances in the gameplay. A lot of the actions would need to be repeated many more times in order to keep the animation flow and prevent animals and people sitting or standing around with nothing to do, while other things that affect the game play need to be spread out a lot to preserve the delicate balance between cost/income, animal needs and guest happiness. E.g. guests would have to find many more things to do in the zoo and stay much longer without spending any more money, without visitng the same habitats five times and without getting bored and more upset about things.
Frontier has repeatedly said that they are looking into it. But looking at the work that would be involved in creating a slow mode that is fully integrated in the game and can be toggled seamlessly with the standard modes (which are purely based on speeding up everything by a certain factor - easy peasy in comparison to what you are asking for; in addition, any changes to the existing standard speed modes would need to be repeated separately for the slow mode), I’d rather have them fix bugs and develop more animals and maybe also more Career scenarios.
You already have Sandbox mode where you are able to play without being interrupted by that many messages since you can basically deactivate everything. You can enjoy your animals to the fullest. If you don’t want to play without the challenges of the Franchise mode - taking care of everything in your zoo is part of it. You can definitely reduce the amount of messages by reducing the number of breeding pairs, training staff, defining workzones, etc., but there still will be times when hands-on management will be necessary. That’s what makes it a management game after all, and the two non-Sandbox modes are not called Challenge and Franchise for nothing.
