Do you have helpful advise to provide? Your saying how they are doing it wrong but are not explaining what to do right. I spam group heal/shield on SCH if i do it after an attack the shield gets applied, and if they get healed to full health they still have the shield up. Its not always mana efficient to keep shields up for an entire fight. Some fights have random mechanics that you cannot always predict when a shielding spell will be needed. Some players just don't do mechanics and can loose shields even if applied “properly”. They still get full benefit of full shield if they are healed at 10% health or 100%. The shields do have a timer so again they are had to just keep on an entire fight.

If they change shields to last until they are used up and not run out after 30 seconds it might change how people use them.