Gee - I never thought about it like that. If I've learned anything about Deathstroke - Slade - it's a running theme I see in his appearances is that he likes to "hurt" his enemies emotionally before he actually fights them. Maybe going after Robin was his way of trying to get at Batman. Kind of like saying - I'm going to take everything you care about and make it mine. But what he didn't count on was that Robin was coming into his own as a Hero himself; he didn't count on Robin fighting back.
But still, I guess I wanted Batman to appear to make it alright again. I have a theory that Teen Titans - is connected continuity-wise to Batman The Animated Series. Partly due to an episode of Static Shock where Batman implies that Robin is "With the Titans" when asked why he's not around anymore.
But mostly due to the episode of Season Five "Go", that explains how the Team began, it shows Robin as mostly dark and brooding - and when he's asked about Batman, he says he works alone now.
It reminded me of "The New Adventures of Batman" - the sequel series to the Animated Series. One episode "Old Wounds" acted as a throwback to the TAS Series that explained that Robin and Batman were growing apart, and not revealing that Barbara Gordon was Batgirl was the final straw. He quit and left Gotham to reestablish himself in a new city as Nightwing.
So you can see why I'd connect the two - the only real difference is Cosmetic, as the two Robins character designs are different. But I feel that - judging by attitude and the particular robin costume, that both Robins are Dick Grayson's character. That and the fact that Robin does eventually become Nightwing in "How Long is Forever".
The reason I wanted Batman to make an appearance at least some point in the series, because I know that Robin and Batman ended on bad terms. I wanted him to appear so that they'd be forced to confront what happened, and maybe reconcile. AND have the obligatory scene where Batman expresses how proud he is that Robin has really come into his own as a hero. Maybe it could've come later in the series, but I feel like Apprentice would've been perfect.