The USA refusing to use Hobart's funnies was one of the reasons they had higher casualties, that, the totally ineffective shore bombardment and the awful tactical bombing that mostly ended up 5 miles behind the beach.
It was just a mess and many young men died horribly because of that.
There are always alternative plans suggested in hindsight. As we gather intelligence after the fact of troop movements, supply routes, and other various strategic information, military analysts will always find a way that the battle could have been done differently that may have saved lives. This is the inevitability of war. The problem with analysts is they never have the responsibility, so they never understand the weight of such a decision. Information may have been available, but the reliability of that information was more stringently questioned than, for example, WMD's in Iraq.
Yes, there was no way of going up and taking that beach without losing a large amount of troops. This beach though also had to be taken, and there was no way around doing what they did. A lot of brave men died there, but it was all needed to win.
The bombing from air and water could of been more effective and though out more. Naval battle ships should moved closer to the beach
from the start. Better intelligence of German troops at Omaha should of been done. Perhaps OMAHA beach could been out flanked from attack from other beach heads instead of frontal attack
The presence of the Axis was too strong and too impossible for the allies to penetrate in 1944. D-Day was a scary and trying time for the forces, and the lives that were lost were tragic. But it was a sacrifice that needed to happen to end a evil empire that could cause mass suffering.
I think the military commanders behind the invasion knew that there would be a high number of casualties when they initiated the operation, I think it was a necessary decision that they had to make to alter the course of war in France, Operation D-Day was a major turning point in the war.
If one has observed "Saving Private Private" one may believe the Movie may have re enacted what may have occured on D-Day (1944). D-Day was critically important to the Allied forces push to retake France and much of Europe, thus a turning point in the War. Sure, 160,000 troops were basically needed in the push and thousands were sacrificed on the beaches of Normandy. I believe casualties were NOT avoidable on D-Day. It will always be something we can see better in hindsight but at the time the allied forces thought that casualties were inevitable.