Or in other words your budget determines your “ideal” with how abundant gear is on p1999.
For soloing or group content most people would recommend just using your best DPS ratio weapon in your bags (typically a 2h after the level 20 damage cap increase) to keep fights as short as possible and therefor taking less damage overall then additional shield AC/stats would have mitigated. Also consider there are less enemy ripostes and less enemy Damage Shield hits being taken while using 2h weapons. If you need a shield to bash, like to interrupt vital spells such as gate then certainly swap one in when needed.
There are rarer end game tradeable Knight class 1h that have significantly better DPS ratios then your halberd but consider if spending tens of thousands of PP for improved damage on a class that uses spells to tank and hold threat is worth it over your 200-400pp halberd when you could spend the money improving your durability with better armor and Hp jewelry. Or spending it on getting convenience items like Jboots.
For comparison:
2h “budget?” upgrade
http://wiki.project1999.com/Exquisite_Velium_Battle_Axe
Vs
1h “budget” dps downgrade
http://wiki.project1999.com/Noctivagant_Blade
Vs the “ideal?”
https://wiki.project1999.com/Massive_Dragonclaw_Shard