Not that I need to say this, but even if any of us would have played it differently, that doesn't necessarily make it a better way to play. Had your opponent's wait been different you might have pressed forward and won as dealer with a nice hand. It's not impossible that your opponent could have had a different wait even with the same discards.
Having said this, I've recently started trying out a much more defensive style where I (usually) remove incomplete melds that are not likely to be used in my final hand as early as possible, even though this limits my ability to change the shape of my hand later. Due to limited availability of mahjong resources, I'm not really aware of whatever existing opinions there might be on doing this, so I'd be interested in getting your (and the rest of the board's) thoughts.
To illustrate, on your fourth draw, your hand looks like this:
Draw:
You have a pair, one complete meld, and three incomplete melds with double-sided waits, which is enough to assemble pinfu dora 1 and reach for it. The 3d, South, and Chun are not part of this final hand. Among those, the 3d is generally less likely to pass later in the game then an honor tile, so (unless I was going to fold now), I would discard the 3d now.
On the same note, the very next turn, you bring 8d into your hand. This gives you [3-56-8]d, which is a nicer shape than [-56-]d, but you already have one complete meld and two other incomplete melds with double-sided waits elsewhere, so you only need one meld from dots. If you keep pressing the hand, the most likely outcome is that you'll have to get rid of the 3d and 8d anyway.
If you were to continue as I described, by the time your opponent declares riichi, your hand would look like:
Draw:
This has the (minor) advantage that you still have the safe Chun in your hand which you can use to get past the ippatsu chance. The South is not necessarily safe, but buying even one turn with the Chun lets you see more safe tiles, as well giving the possibility that someone else will deal in or the opponent will self-draw.
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As for the specific moment you were in when your hand looked like:
Draw:
In order to make this hand proceed normally, you're going to have to dump 1c, 3d, and 8d, and only the 3d is safe among those. There is no particular reason to think that the 1c is safe; rather, it may be that the reason the opponent discarded the red 5c last is because he had something like [-23-5] and was waiting to see whether he would draw the 4, in which case he could connect the red 5 and keep the dora.
Because I'm East and behind, I don't want to completely give up on the hand, but that's a lot of danger tiles to go through for this hand. Because the opponent discarded quite a few middle bamboo tiles early, I would plan to discard my bamboo tiles down to only one meld and then see if I happen to get the needed 4d and 7d which allow me to keep the 8d and have two melds in dots. If that happens, then I can decide at that time whether the risk/reward of discarding the 1c is in my favor or not.
I would start by discarding the mostly safe red 5b (I say mostly just to emphasize that someone else would win on it), with the possibility of discarding the 6b in the future if a later draw improves my hand.