I'll cut the trend and say I don't think I want classic Sonic to have a voice. I don't really like Jaleel White's Sonic and I think the voice would just be disappointing to me no matter what.
Wasn't it some SOA person who told Sonic Team that the fandom would be livid if Classic Sonic wasn't Jaleel White (and thus lead to Classic Sonic being mute)? I don't know why SOA had to meddle. I personally wouldn't want Jaleel White to do the voice. Besides, they got a new person to do Classic Tails and I don't think anyone objected to that (I thought Classic Tails was spot on).
That was http://kotaku.com/5846911/sonic-will-meet-sonic-in-sonic-generations-and-other-amusing-revelations He was probably joking. If he wasn't, doesn't seem like there's anything indicating classic Sonic's mute cause of Sega America meddling.
Classic Tails was voiced by Kate Higgins, who also voiced Modern Tails at the time. However, since Boom, Tails has been voiced by Colleen O'shaughnessey, that's the same person who does Charmy's voice, as Kate left. Classic Tails' voice will change of he reappears in Forces. Though honestly it's almost impossible to tell that Modern Tails' voice has even changed. If Classic Eggman is back, I hope he sounds a bit different this time. It bugged me that both Eggmans (Eggmen?) sounded identical in Generations.
Why would Robotnik's voice change? He's a grown adult, after all, it's not like he's aged that much like Sonic and Tails.
I suppose having slightly different voices makes it easier to tell them apart. Although going by the character ages, none of them actually aged, so they should all sound the same. (Sonic's age was listed as 15-16 in the classic games, and 15 in modern, while Tails has always been 8).
Because it's really weird giving two characters the exact same voice when they distant greatly in appearance. Rush just about got away with it with Eggman and Nega, but when they got full.voice acting in Rivals 2, Pollock was directed to give a unique performance fire Nega so that they could be differentiated. I'm not asking for a difference of even that calibre - just something so that you can tell the two of them apart.
I would kind of like Classic Robotnik having a bit of AoSTH flair to his voice, or if not that, just give him a different speaking style. Pollock is certainly capable of giving different voices for essentially the same character, look at Boom Eggman for example.
Boom Eggman sounds exactly the same though? Unless you're talking about specific instances where he does things within Boom. Pollock has got range though. If he was told to try and do a different voice for Classic Eggman, I'm sure he'd come up with something. IIRC, it's been mentioned that they do sound different in the Japanese dub, but I'm so unused to hearing Japanese voices that I can't tell them apart. I wonder what they're like in the other languages. I'll have to give them a listen later.
Idk how to describe it, but Boom Eggman seems to have a higher voice and is more expressive and excitable while Standard Eggman's voice is slightly deeper. Like if there was a scenario where both of them spoke there would be some noticeable differences. It's kind of hard to say though, as there haven't been a lot of games with Modern Eggman since Boom came out, so outside of Lost World all of Pollock's Sonic work has been for Boom Eggman.
Roger's Sonic is about as young as he can sound TBH. I don't think he literally can sound any younger than he already does as Sonic. I think Johnny Yong Bosch, even though this will elicit groans due to him being cast in so many things, could very well wind up being Classic Sonic, because he can sound much younger than Roger can and still provide the signature Sonic sound. That's if they decide to give Classic Sonic a voice anyway.
If they were going to bring in new voice actors for classic Sonic and Robotnik, anyone besides Jaleel White and Jim Cummings would be unacceptable.
It's more than likely due to the different general voice direction that Boom has (better, IMO) than Pollock actively changing his voice simply because it's a different incarnation of the character. After all, just about everyone sounds different in Boom, and the only case where I'd say it's specifically to fit a personality change is with Knuckles (even if Travis is basically just doing his "Drunk Roy Mustang" voice for an entire show). It's less a case of the voice being definitively different, just the actor doing a better performance.
RE: Comparing Link's and Classic Sonic's lack of spoken lines. The notable difference is that in the Zeldas (dunno about BotW since I've still not played it), NPCs act as if Link is actually talking but the player can't hear him. Classic Sonic just explicitly doesn't say a word in Generations, which is acknowledged by the other characters. Thing is, it was played for laughs and in a kinda cute way, so I can't say I didn't like how they handled it then. Now, doing it again for SF may not be a good idea, as jokes wear off when doing them over again.
Eggman sounds different in Boom because Boom Eggman is a different, markedly goofier character, saying markedly goofier things. It isn't better or worse voice direction. It's just different.
In other Zelda games it worked because of exactly what you said and it still works in Breath of the Wild but in the cutscenes they will sometimes ask Link direct questions and look up at him expecting a response and then say things like "No, you don't have to say anything," ect. (The cutscenes have spoken dialogue.) There's a lot of moments like that in the cutscenes that make it kind of strange that he lacks a voice. It doesn't really bother me or anything and I can understand why they decided to keep him mute. I've loved every Zelda game that's ever come out. It's just something that I noticed while playing the game because now that everyone has a spoken voice and talks it's kind of strange that he's literally mute in every cutscene lol. It becomes more awkward and noticeable when he's asked direct questions and never has a spoken response but it doesn't really bother me. I liked how Classic Sonic was handled in Sonic Generations. He was cute and funny and I think they did a good job of showing his attitude and personality through his body language and expressions. I don't mind him being mute or if he had a voice. I'd like it either way. If they decide to keep him mute in Sonic Forces I wouldn't mind. I think they could still do it without it becoming tired or forced. (No pun intended lol.) I just hate the fact that a lot of people have this idea that Sonic never spoke at all in the classic days. It's just that there was no speech or dialogue in the Megadrive titles but I bet if technology allowed for it at the time there probably would have been games with speech and dialogue in them just like how Sonic CD had random spoken dialogue and the classic arcade games did.
I can only associate classic Eggman to the Sonic OVA. Any other voice to him just doesn't really fit his cape flaps.
When Sonic X first started, Pollock was going for more rougher voice similar to that of Deem Bristow, does that count?