uh, Really? I noticed the extreme opposite.
both in the "openness" thing and the "chemistry" thing.
BEWARE WALLOFTEXT BELOW, USE YOU SCROLLBAR TO SKIP THIS SHIT.
I see Blaze being rather closed to Silver in Sonic '06, acting just like an older, more responsible sister figure, guiding him and constantly reminding him of the task, she didn't show any weakness or vulnerabilities to him, actually, Silver was the one who opened up and showed his vulnerabilities and insecurities to her while she was the one supporting him and reminding him they were fighting to save the world at all costs.
this is ultimately clear in Silver's ending where Blaze is the one who tells Silver that they should be focusing about the task of saving the world, while Silver was more worried about Blaze's own fate:
Silver valued his bond with Blaze more than saving the world, being herself Blaze knew that was a massive stupidity at this point, but she couldn't be mad at him... THAT is why Blaze calls him naive in the end.
She had the role of a supporter, she was the one guiding Silver with his problems and she was the one reminding him of the mission, her own position prevents her from showing him any weakness or vulnerabilities, because Silver was the one who was insecure, not her.
contrast now her interactions with Sonic in Sonic Rush, the table flips completely, there, she is the one who shows being emotionally vulnerable, while Sonic this time, was the supporter, notice how she was actually pretty troubled when she was fighting Sonic:
it's the whole reason why she was a quite of a bitch, she thinks of her powers as a curse, so she isolated herself, doing everything alone, when someone tries to help, she flips her shit, she told him everything, she literally had an emotional breakdown there.
it's a completely different emotional exposure to the one she shows to Silver, with Silver she was the supporter, here she is the one who will be supported, I would say Blaze opens herself much more to Sonic than she did to Silver in all of their interactions.
as you will see next, their bond is not only because of power of friendship and stuff, it had a reason:
the reason Sonic and Blaze become close is because he actually tells her that her powers are not a curse like she always believed her whole life, being him and cream one of the very few people who did not fear forming a bond with her, she changed her whole outlook on how she behaves and feels about herself.
that's why I see Blaze being much more open to Sonic than she was with Silver, with Silver she was the strong figure, she shown no weakness in order for her to support him, with Sonic, he was the one who dealt with her vulnerabilities.
in the "chemistry" subject...
I don't see it that way... I would risk my neck and say they Silver and Blaze had near zero romantic chemistry.
of course, they were, friends, they had a bond and liked each other, but nothing in the games ever pointed to a romantic relationship between Silver and Blaze, you never see them interacting with a hint of attraction or desire, actually it's quite the opposite they have lots of "hints" that point to a platonic relationship instead of a romantic one, I might use the example of the "test of love" where Sonic, Amy and Elise are involved (heck AMY, is used as a love interest there) while Silver and Blaze have the test of friendship, (memory and mind, if I recall correctly)... but no mention of romance here or anywhere in the franchise, and the reason for that... is actually quite simple:
according to Sonic Team, Silver and Blaze were not meant to be seen as romantic partners.
their relationship is described by the director (and one of the writers) of Sonic '06 as the one of a brother and a sister (that same guy said Sonic and Elise were actually attracted at each other, oh lord, back to the subject), a sibling like relationship, which is... fundamentally platonic in nature, knowing that I would say again that they are not seen by them as a potential couple, at all.
when you see Blaze and Silver together in the new games, they are not hinting at a couple, they are also not hinting at them being friends, they are actually alluding to the former sibling like relationship they did share in Sonic '06, it's rather nonsensical as they are both completely unrelated characters with different backgrounds, and I don't know who was the "genius" who had such idea, but they keep doing that nonetheless.
that being said contrast Blaze's interactions with Sonic, an example of how romance is used in context to hint at characters relationships, now I'll just use the easiest example, the "Percival's Defeat" cut-scene in Sonic and the Black Knight.
now, forget everything about the scene, forget the dialogue, forget the acting, forget the blushing, forget that Percival is not really Blaze, i'll just focus in a small fact that is quite telling about the interpretation of the characters:
the Storybook series always had some tidbits of the interactions Sonic has with his friends and allies using the characters as "doppelgangers".
You see Sonic and Sindbad bickering just like he does with Knuckles, you had the blacksmith handling gears as Tails do, you see Sonic trying to run away from Nimue at first just like he does with Amy before things cool down, Sonic notes to himself when he sees Lancelot that "some things never change" and with Percival who is Blaze, (also, funny to notice, Percival's partner is Galahad, who just happens to be Silver) Sonic has... a scene filled with romantic implications.
the thing is, Sonic Team is surprisingly comfortable with trowing unambiguously romantic implications at Sonic and Blaze, mention of jealousy and kisses, characters gazing at each other, blushing and such.
following the logic that the interaction with that doppelgangers mimics the interaction Sonic has with his friends, the hint would essentially be, that just like Sonic's relationship with the other characters are described by his interactions with the doppelgangers, Sonic's relationship with Blaze would essentially be described as containing some sort of romantic affection, desire or attraction, and not just a platonic friendship with no implications whatsoever.
I don't know who likes who, but that angle is definitively there.
notice however that they still don't forget to allude at Blaze's partnership with Silver.
so back to my point, of who Blaze has more chemistry with.
in the former case Silver and Blaze are described as being like brother and sister, describing a completely platonic relationship in a game that had no fear of touching the romance subject with Sonic and Elise, while in the other case has Sonic and Blaze sharing a scene with rather blatant romantic implications, (which by the logic means at the very least that officially Sonic Team doesn't minds the public seeing as romantic partners at all).
in the end for me... is no contest, Blaze would be both more open and have more chemistry with Sonic than with Silver, I see the writers never meant to make Blaze a love interest for Silver, or for that matter hint at a relationship that goes anywhere beyond being platonic, with Sonic however...