Hi Christina.
I think speed was a factor. You are correct in that it was the practice among these fast mail steamers not to slow down when visibility was good until danger was actually seen. But the damage done to the ship during a collision has everything to do with its speed because the energy of the collision goes up as the square of the speed. In other words, if the ship was travelling half as fast the energy of collision would have been only 1/4 as great, and the amount of damage would most likely have been far less, probably not enough to sink the ship.
When you mentioned about ice warnings being ignored I assume you mean that the ship's course was not changed to stay well clear of the region reported. I agree.
I also agree about the issue of binoculars for the lookouts. But what could have been done was to increase the number of lookouts knowing that they were entering a region of ice. There were two up in the nest, but nobody stationed on the forecastle head where they had a telephone connection to the bridge, and at the time of the collision, only one officer was out on the bridge looking out.
As far as putting the engines in reverse, there is only indirect evidence that that is what really happened. The evidence from down in the engine rooms from at least 3 different sources say that the ship never went into reverse before the collision took place.
Lifeboats, well that rule was of course obsolete.
As far as the bulkhead heights go, the ship was not designed to have 5 compartments opened up to the sea. What most people don't know is that the Titanic could have stayed afloat if only the first 4 compartments were compromised. In a sense, it was better designed than some ship of today. Nobody ever thought there would be an accident where the first 5 compartments would be damaged. But even so, her design was such that she managed to remain mostly stable for 2 1/2 hours. That is something you rarely see even on modern ships that get damaged below the waterline. A sharp list in either direction could easily negate having enough lifeboats for all. Maybe for modern cruise ships the requirement should be lifeboats for all on both sides just in case.
By the way, if you ever go on a modern cruise ship and walk fore and aft along any deck open to passengers, just ask yourself (or crew member) where are all those high watertight bulkheads with watertight doors? And while you're at it, just hope the ship doesn't run into an uncharted submerged volcanic reef, say off the the Hawaiian Islands or in Alaskan waters, while running at full ahead speed.