Heya, just finding out about this thread now, so I'm sorry if what I say has already been stated at some point, but I didn't read through all of the pages. Anyways, the point I want to make is that Summoner still feels like it's lacking as a class at certain points in progression, and especially in prehardmode and the early game. Now the whips are a great addition, and I think they are very great, but there's only 2 of them in prehardmode, and as for minions there's only around 5 total in prehardmode as well. Although its a step up from 1.3.5, it stills feels incredibly lacking. New weapons entirely are likely not going to come since this is Journey's End after all, but I think a few balance changes could go a long way to make the Summoner a bit more viable and fun to play in prehardmode. Here's what I would suggest.
1. Buff the Finch Staff. The Finch Staff is a great addition, to give Summoners at least some form of prehardmode minion to start with. But, it feels pretty underpowered, and kind of reminds me of the Wand of Sparking pre 1.4. It's good for giving Summoners a starting push, but considering it makes up 1/5 of all the prehardmode minions you can find, and it's likely are you are going to use for a while, it seems very weak. Not only does it have low damage in general, but the pure inaccuracy of this weapon makes it kill enemies painfully slow, especially in tougher difficulties. I know the devs don't encourage playing as only a single class, but I wanted to try it out to see how much Summoner was improved. Anyways, my point is that the Finch is very weak against anything but slimes. What makes this even more punishing is that it can be a bit hard to find, as it's not super common or craftable. Perhaps it should be added as an item available in all wooden chests and wooden crates, similar to the Wand of Sparking, instead of a rare item from living trees. Anyways, the lack of power in the Finch leads me to my next point
2. Make the Leather Whip a bit easier to get. Now I am a huge fan of Whips. They are a really cool concept and feature, and it fleshes out the class a ton. My problem lies with the fact that the Leather Whip, which is a solid weapon in general and is meant to be the first whip you get, is only obtainable when you fill out 15% of the Bestiary. This isn't too big of a problem in Multiplayer, but since I decided to challenge myself and only had the Finch, it took ages to kill enough enemies to unlock it in the shop, and this was only made harder by the fact that the Finch is weak in general (so making it better would lessen this problem too). Another change I would suggest is to lower the price on the Leather Whip a bit since it's pretty expensive as a starter weapon. The Snapthorn is a great weapon, and there's no real reason to get the Leather Whip, because rushing Snap Thorn is an all-around better strategy, since both are available pre-boss, and the Snap Thorn only requires you to kill enough enemies that drop Stingers to obtain. The Leather Whip should be easier to obtain in order to encourage getting it before the Snapthorn, and making it more useful.
3. Buff the Vampire Frog + Make it easier to obtain. In terms of weapons being underpowered or too hard to get (which is a bit of a theme with Summoner gear in general) the Vampire Frog is a pretty cool idea for a minion. The idea of getting it is unique too, which is fishing in a blood moon. However, even with the right setup and gear, Mermen are incredibly strong, and the Finch does not cut it in terms of killing them (honestly in general they are strong against most of the pre-boss teir weaponry) So your likely to not kill too many in a single blood moon. The rarity of the blood moon, combined with tankiness of mermen, combined with the rarity of the drop, makes the Vampire Frog an incredibly painful weapon to grind for. The worst part is that it also feels pretty underpowered once you get it. It's not inherently super bad, and the idea of a land minion is cool, but they aren't super good against fast or flying mobs, and they are kind of needed considering its the best minion you can get before fighting any bosses. What I would do is raise the drop chance a fair bit, and make the minion stronger in general.
With these problems, there are only really a few truly "Viable" weapons available to summoner in prehardmode, and (not counting the Ballista Staff or other Tavernkeep entries) would be the Snapthorn and Imps. Leather Whip is easily skippable, Finch is very underpowered, and the Frog is too hard to get, so the best option would be to grab a Snapthorn from the jungle and whip the EoW/BoC to death, and then use your new pickaxe to obtain the imps, and decimate every other prehardmode boss. The problem with summoner in prehardmode before (besides lack of items) was the fact that all you really had to do was get a Reavershark and rush Imps, making all other Summons invalid. In 1.4 it is practically the same, except replace the reaver shark with using Snapthorn against the world evil boss. Most weapons are either too weak or too hard to get to be considered viable, which is a problem with Summoner throughout the whole game, but most apparent in prehardmode.
One last point I have is, and its a bit of a lesser one, the hornet feels a bit weak too. Its certainly pretty good, but in the face of the new and improved imps (and the fact that you will likely get the imps sooner) I don't feel like there's any real reason to use the hornets.
Anyways sorry for making you read through this wall of text. My complaints come from a place of love for Terraria and admiration for the people who work on it. The Summoner is my favorite class, so the flaws in it are apparent to me. The unique playstyle and the challenge that comes from it is really fun and interesting.
TL;DR - Buff the Finch and Vampire Frog, and make them easier to get. Also make the leather whip easier to get so it's worth obtaining before the Snap Thorn