The problems with Rift Herald
After over a year since her addition to the game, Rift Herald still isn't in good shape. While the jungle's ended up with some less popular objectives, e.g. Ocean or Cloud Drake, Rift Herald has remained consistently unpopular, and rarely feels worth committing to. Riot themselves have been questioning its usefulness, and considering its removal.
The thing is, Rift Herald at its core is a brilliant idea, as it's perfectly suited (in theory) to making top lane feel less isolated. The core issue now, though, is that Rift Herald's buff forces whoever picks it up to isolate themselves in order to make it work: when around an ally, Glimpse of the Void provides no damage reduction and cannot gain charges, and since teams tend to group up fairly early, the buff feels wasted in most cases. Even when the buff is active, it's not really game-changing, and despite being made for splitpushing, it doesn't really help if the top laner doesn't have the team pressure they need to apply it. The fact that the buff runs out eventually also means it can't be used to make that extra push in close, drawn-out games.
Basically, Rift Herald just doesn't really provide anything truly worthwhile or functional right now, and its buff needs to change completely. Hopefully more can contribute ideas here, but here are some of mine:
#Solution 1: Replace Rift Herald's Buff with Baron Nashor's team-wide enhanced recall
The idea here is to a) favor splitpushers by giving them the team pressure they need, and b) make Rift Herald feel worthwhile to the entire team, thereby de-isolating top lane a little. Rotational power is extremely valuable at all tiers of play, and a 4-second recall can really add up over time, as well as provide more options to players still in the laning phase. An advantage to a bonus like this is that it would also be less binary, since it would allow teams that are behind to consistently recover faster, and make use of the buff more often if they're under heavy lane pressure.
#Solution 2: Remove Rift Herald's Buff, and instead allow the killer to spawn a massive void minion (maybe another Herald) that travels down a lane and fights for their team. This is a one-time consumable buff.
Probably more far-fetched, and would likely require a lot more adjustment, but the idea here is to allow the top laner to lay down a major pushing threat down their lane, while they begin roaming elsewhere and interact more with the rest of their team. This could potentially also benefit the mid laner, especially if they're an assassin, since it would compensate for their weak pushing power and let them roam a lot better.
An effect like that could potentially be pretty snowbally, since an advantage in top lane could chain across to the other lanes, but that could potentially be a good thing: Riot's been looking for ways to make the laning phase feel more impactful, and so far has implemented a lot of not-so-great mechanics, like minion pushing power and tower first blood, in order to achieve that. Making Rift Herald a popular and effective early-to-mid snowball option could potentially provide enough early momentum for those mechanics to not need to exist.
Other than that, I think there are probably some other, more minor issues with Herald (e.g. the on-hit percent current health damage it deals, which isn't good for the tanks and fighters the objective is meant to cater to), but really the problem is its buff, which needs a complete redo.