Sorry i'm late to this thread, but I just came across it yesterday and wanted to add my own thoughts.
I love 3.5e above all other D&D editions, and to this day it’s my go-to. I’m not a purist; I enjoy B/X at times, and have many fond memories of 1e, and I’m currently playing in a 5e game. I’ve played a lot of other games, too, like TMNT (fun!), Gamma World, GURPS, Fate (fun in small doses), Deadlands, PF (via Kingmaker), and more. However, 3.5e hit my sweet spot, and nothing has had the same staying power. To me, I think that the character customization and flexibility of the system are two of the main draws. I find that I really enjoy games that allow me to think deeply about how to construct a character (or vehicle, or squad, or
something) and then take that something to engage with the game and see how it plays out. In 3.5e, character building is part of the game. If you don’t enjoy character building, you’re likely not going to enjoy 3.5e
as much. But the flexibility of the system is also great, and I find I can run a wide variety of games using the system.
Having said that, there are definitely some weak points for the game, and when I DM have some house-rule changes to ease them.
CR system. The CR system conceptually is a useful tool, but in application is incredibly inconsistent. To make it more useful, I’ve found myself doing the following:
- Class levels are discounted. Generally CR = 75-80% of class level, but I do eyeball things. Sometimes I’ll place it higher, sometimes lower.
- Some stock monsters are completely imbalanced, either too high or too low. If I want to use these I’ll generally re-work the monster.
- On a related note, monster designers were too rigidly confined to the rules for things like attack damage (based on size), or basing special abilities off of existing spells, and missed out on a lot of interesting design space. This can lead to ludicrous results like a CR 19 creature with attacks that do 1d8+2. I will sometimes take more liberties to make more interesting opponents.
Rogue Sneak Attack
- Rogue Sneak Attack is much too restrictive and unworkable most of the time. It’s soooo easy to neutralize this ability, and it’s really the biggest thing Rogues have going for them. Just go the 5e route.
Magic Items
- Assuming characters have universal access to buy/sell/craft any item they want to creates the problem where every player is incentivized to build out the same boring inventory of +x armor/+x resistance/+x deflection/+x stat item. It both discourages interesting magic items and encourages boring char-op. I house-ruled a magic item economy system that I’m pretty happy with for now, but this is an area a DM has to consider carefully.
Skills
- These are way too restrictive, especially as a lot of classes have “required” skills, which means that no one will ever take interesting skill choices that improve the quality of the game. In my current game I give everyone 1 SP/level that they must spend on “background” skill, with the caveat that they can never exceed 1 rank/2 levels by spending a background skill point, and the list of eligible skills is limited (knowledge, languages, craft, profession, etc). This helps, but it’s not perfect. I like the PF approach of the first rank giving a +3 bonus, and I’m also open to increasing the number of background SP or something similar.
Feats
- I don’t think the designers realized how few feats PCs get, or how restrictive some of the feat pre-requisites are for 25 point buy. I reduced stat prerequisites for feats by 2 across the board, and I’ve considered giving every PC more feats. I like the PF approach. That being said, I haven’t changed the number of feats yet, and it’s more a quality-of-life thing than a “this is broken” thing.
- Quite a few feats overly value minor bonuses. I’ve tweaked some to make them less fiddly and more attractive. For example, Dodge gives a flat +1 Dodge AC bonus against all opponents. Greater Weapon Focus stacks with Weapon Focus. Toughness is replaced with Improved Toughness. etc.
There are a number of other things about how I run my games that prevent shenanigans that might make the game less enjoyable:
- I control access to prestige classes, and they are tied to the setting. A prestige class plays an actual role in the setting, only a few are available, and pursuing the class comes with in-game expectations.
- Multi-class XP penalties - yes, of course. Although it’s only ever once been an issue.
- Core-only by default. Everything else needs to be approved by me, and is subject to modification. I’m pretty easy-going and only change or reject things rarely, but it avoids the worst of the cheese.
- I’m more permissive about increasing the abilities and power of martial characters, and more restrictive about increasing the abilities and power of magical characters.
As far as high level play goes, I admit I don’t have vast experience. I had previous campaigns reach 14th (we had to quit when I moved away), and then 9th, and my current campaign has just reached 12th. I’ve heard about issues with scry-buff-teleport, but have yet to really run into any problems in any of my games that made the game less fun. The 12th level barbarian and 12th level ranger are having just as much fun as the 12th level sorcerer, and are just as vital to the group’s success. The game changes as you get to higher levels, but that’s pretty true for any game, isn’t it?