Normally the risk of doing dragon early is that you lose out on so much time/health that the enemy jgler risks falling too far behind that you avoid doing so until you have killed bot (or sometimes mid). With basically all dragons (except infernal) being too strong to solo early game you cannot do it early now. (Infernal is almost always warded early because it's easy to solo and the most contested for obvious reasons)
With nerfing dragon health it becomes a lot easier to take and you can actually do something like
- Top jgl -> Bot -> Dragon
- Clearing Bot -> dragon -> top side
- Top -> dragon -> bot
Some of these might not actually be able to be punished in some match ups because of how certain champs needs to clear a certain side. On top of how some jglers has it a lot easier to do so with the lvl 3 from blue buff jgler now.
The early dragon health now is what makes it needed to be at least lvl 4-5 with a full jgl item before it can be soloed.
Furthermore, what is the feedback on how this will impact mapsplit in proplay when you now can do dragon at lvl 3 at the basically the same time span it takes to do krug camp? This means dragon is essentially a free scuttle with a teamwide buff if you split the map so enemy jgler cannot contest dragon. With herald not spawning until 8 minutes enemy jgler cannot do that in return regardless