Leagues aren't just designed to give fodder monsters for maps, they're about exploring how to added different features to the game and at times they're not gonna be for your playing style but as an option to play the game differently.
1) Why have the nets be consumable? 2 obvious reasons I can see are this: First nets pretty much freeze the target, giving you that without a cost that you can just do forever. Second, if nets have no costs, that means every legendary beast is a guarantee to be captured, and if they want to give powerful crafting mods as an incentive a reward for engaging , that would mean the legendary beasts would have be incredibly rare to encounter. Then everyone will complain about never seeing them. If you want giant rewards they have be rare or cost you something or have potential risk.
2) Why tiers? didn't they learn from talisman? Well apart from the word tiers, this is has little in common with what was wrong with talismans. Tiers are there so that people would not feel the need to horde nets, it means you can get really helpful leveling gear and you can interact with the league while leveling if you choose to. Nobody uses Chaos Orbs or Exalts while leveling, hell, people hardly use any poe currency while leveling. Adding level-bound currency means that low level players can use them and not feel like it's more beneficial to trade them to players farming thousands of Chaos per hour who would otherwise get better use out of them and have the resources to purchase them.
3) Why the rng for them not to be captured? well a few reasons. first if it was a 100% capture rate then you would have to make it so that you can only throw the net when they're at low life. otherwise this just 1 hit kill on any legendary beast. And since everyone is clearing so fast, they want you to be able to throw the net at 100% life before you attack and kill it too quick. In order to let you throw the net at 100% life it can't 100% capture. And as far as complaining about rng as a concept, rng is in every part of this game, breach had rng on the location in the map, the type of breach, the amount of monsters swarming, hands and splinters, bosses dropping uniques/blessings. This isn't the first league with rng and it won't be the last.
If just full clearing easy maps super quick is how you want to play just do that, but understand that your way of playing is not "THE" way of playing the game it's just A way of playing the game. There are many different ways to make money in the game that don't involve sextenting channels all day that you can play in different styles and still get what you need to make builds in the game. For more Path of Exile tips and tricks, stay tuned to U4GM. You can choose www.u4gm.com where you can buy exalted orbs cheap.
The Wall