Me personally? I think it would be interesting to see Depth Charge interacting with Blackarachnia. I don't think they'd get along too well, especially considering how she stole the TMII driver from right under his nose. If he found out that she stole the device just to gain power for herself, I think that whatever trust he had for her to begin with(probably not much) would fly out the window. The reason he tried to destroy the device in the first place was to prevent anyone else from using its destructive powers as indicated by his line, "Never again, Megatron!"
Depth Charge isn't the type to forgive or forget things like these and I think that if he found out Blackarachnia used the TMII device on herself to gain more power, he'd most likely add her to his hit list, making her second in line after Rampage. That's probably the most realistic interaction I can see happening between the two... the two of them at each other's throats. It would definitely be interesting to see but unfortunately, the writers decided to gloss over this potential sub-plot.
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That's my speculation on how the two would interact. Any specific character interactions you guys would like to see?