Maybe have saves work like this. The snake attacks against the PC's AC or DEX score (with "flater math" DEX would be the DC) does normal bite damage and then the PC makes a CON save to see how virulent it is. The Mage rolls to hit the Goblins WIS, beats the Score/DC and the Goblin is Charmed. Then, said goblin makes a WIS save to see how long, hours, days, weeks, etc. This serves two purposes: 1) Mage still has fun rolling to hit, 2) The Nostalgia of Saves is still kept AND it fits mechanically as well as story wise.
To expand upon this idea if a fighter bull rushes u off a cliff or a spellcaster moves earth for the same effect (game terms = hitting u with attack or spell) u could make a DEX Save to grap on to something while falling, arrest your fall etc, or maybe a CON Save to take less damage from the fall.
You could make an INT Save to avoid the more detrimental effcts of a MAZE or GEAS/QUEST Spell.
A STR check to be pushed less feet from your original position.
The possibilities are quite endless