TL;DR - I like riot's stance on "good variation", but think random spawning dragons pose a problem. One solution I like would be to show drag spawning order in the pregame lobby so teams can draft comps with dragon types in mind. I don't know if this would be easy to do or not, and it may even be a terrible idea, but I would like to see other players thoughts and ideas relating to it!
In the video, Riot talks about the "variance" (RNG) that they like and don't like in League of Legends. One thing in particular that they talk about is being given varying information and being forced to react to it (the variance they like, such as drake elements). The alternative is having the intent to do an action and then having RNG, prevent you from doing it (bad variance ~ like dodge was back in the day).
In the game's current state, I feel like dragon elements is actually a mix of both the good and the bad variance. Yes, you do get the information ahead of time, allowing you to plan around it, but it can also prevent intent. An example of dragon elements preventing a team's "intent" would be your team picking a late game scaling comp, but having 3 infernal drakes and 1 or two mountain drakes spawn in that order. Now your intent in champ select was to pick a scaling comp, and give up one or two dragons before you were ready to start fighting, but now that the enemy early game team has hit those first two infernals, they are stronger than you for much longer than they would be otherwise. Despite your intent of playing passive early on, you now had RNG roll a "1" and you screwed yourself over.
An actual game that this happened in (i don't remember which game exactly) was like week 9 summer split 2016 with Immortals vs TSM. The aggressive early game team, Immortals finally picked a late game comp, and I was excited to see how they would handle taking a game late. But then I saw one after another infernal drake spawn and TSM ended up with a triple Infernal drake. Immortals did a good job keeping the game close, but slowly lost more and more ground as TSM advanced. Ultimately, TSM had accumulated enough of a lead to win the game.
Now don't get me wrong. I do think there is something to be said about not wanting every game to last 60+ minutes because of late game team comps (thinking of CLG.EU back in the day). Encouraging teams to fight over objectives is important. Also, Immortals didn't play a perfect game, and despite losing 4 drakes in a row, there were probably other opportunities for them to make comebacks and win the game.
What I would think is ideal (and I am some ignorant Gold 5 player who has no programming experience), would be showing what order the drakes would spawn in the pregame lobby. I don't know how difficult that would be to code, but I think it would create an interesting "variance". The teams have complete knowledge on what drakes are spawning throughout the game. If you see 3 cloud drakes initially, maybe that does open up the option of going for a "safe" late game comp, or perhaps you choose to go for a pick comp, where move speed is important. Maybe there was a combination of mountain and ocean drakes that are perfect for a siege comp. This idea would reward teams who draft around dragons while still encouraging teams to prioritize early dragons (and potential fights). Lastly, I think it could potentially (depending on the meta and how strong certain comps are vs drag types) create more diverse matches and champion picks, by encouraging teams to draft different strategies ahead of time.
Whether I am on to a good idea, or am totally wrong, I would like to hear from other players (and possibly devs) about their thoughts on this idea. I think it would remove an aspect of (what I see as) "negative variation" while still promoting the "good variation". Thanks for reading my "essay", and I hope to see some follow up.