While I probably would not do well at all as a game show producer, I got a few ideas for some of the modern shows:
Lingo
I'd actually move the question mark balls to round one and add some prize balls and other crap. Then take those out in round two and play straight Lingo then. Yeah, this might make round one go slower, but having less gimmicks in round two might make that round go by faster. Besides that, I can't think of a way to improve the main game without it having some sort of disadvantage to a team, or that it's self-contained.
For Bonus Lingo, I thought of a concept of mixing old (No Lingo from the 80s run) with new (Current Bonus Lingo). The object is to avoid getting a Lingo, and the team starts out with 10 balls to draw. They try to lower the drawing by doing the 2:00 to guess as many five-letter words as they can. If they avoid a Lingo, it's $5,000. However, if they are able to get ten in 2:00, they get that Lingo jackpot at X value. Also, there would be a Golden Ball that automatically stops the drawing and gives the team the five grand. Not the best of bonus rounds, but it certainly avoid the anti-climatic nature of the current bonus round.
Lastly, get rid of Shandi. Chuck was conversing much better with contestants in earlier seasons when GSN didn't get a case of Icey syndrome and stick Stacey Hayes in there. If anything, a new co-host who has the knowledge of Stacey but Shandi's conversing "skills" (if you want to call it that) might be a good alternate plan if they want to keep the useless blonde co-host.
That's the Question
Seriously, this game is just made to be a toss-up game. Let Goen give the question, let players buzz in, and go from there. Give players an additional point for every covered letter plus the 5 points for solving. Let letters pop in for the answer in round one, but leave it completely empty for round two.
This next one might require that the producers actually use their brains and handpick a question, but gauge the question on how much time the winning contestant has. Less than a minute? Give them a short question. Over two minutes? Give them a longer question. $500 as a consolation seems a bit cheap, I can't think of any other consolation that wouldn't hurt GSN's miniscule budget.
Chain Reaction
I kinda preferred the "You get x points/dollars for how many letters are in a word", so I'd go to that format and double the value of the final word. Get rid of speed chains. The gambling round would be nixed and replaced with a 3-chain speed round where teams try to fill in the middle word in a chain for a certain value.
Bonus round should go back to season one, but nix the blindfold and have the guesser in front of the clue-givers (like in season two). No buzzins, classic bell. $100/right answer, get 7 and you win $5,000. Probably would result in lesser wins, but this is GSN we're talking about.
And if GSN ever decides to revive it (and how much they air it on the schedule looks like somebody likes it):
Whammy!
Get rid of Double Whammies and get more cash, less prizes. Oh, and make Todd Newton switch to decaf this time.
I bet somebody's not gonna like any of my ideas. Hey, there's just so much wrong with the majority of them...