Did my new dentist over-prep my teeth or used an incorrect technique? He removed the old bonding and reduced the tongue side.

Sometimes (usually?) veneers need to wrap around the teeth to hide the edges, so it is common that there is enamel shaping that goes between the teeth and the tip.  Often it resembles a 3/4 crown.  Is there a difference if 0.5 mm enamel is reduced or 1.0?  Not really.  Is it incorrect?  Not at all.  There are many reasons to extend the margins, from bite issues, previous restorations, cracks seen only with magnification and so on.  Even if it ended up prepped like a full crown doesn't mean incorrect, it just means "more".  The fees are the same, time involved is the same....  Nothing wrong.

There are many different acceptable preparation designs and they are determined by the position of your teeth (do they angle forward, backward, are they rotated, worn, too short, too long, do they have cavities or large existing fillings or bonding, are your teeth crowded or are they spaced, etc.), your bite and the type of material the dentist uses (plastic composite, Lumineers, ultra thin veneers, feldspathic porcelain, or pressed ceramic like EMax or Empress porcelain).

In general it is a perfectly acceptable to go over the edge of the tooth onto some of the back (tongue) side.  An important goal for most dentists is, if possible, is NOT to prepare the backside bump (called a cingulum) of the upper incisors and cuspids.  This is a huge advantage of veneers over full crown restorations.  Once this bump is prepared and covered, studies show that the actual tooth underneath is 50% weaker than if the bump was not prepared and covered with a veneer or a crown.

It sounds to me by your description that your dentist did not do that.

But going to the big picture, you have all porcelain veneers and not full crowns (either full porcelain or porcelain fused to metal full crowns).  This means that your dentist most likely prepared your teeth only 10% to 25% of what would have been necessary with full crown restorations.