Here's the short, polite answer:
For me,
Grim Tales (GT) added too much complexity to the game on several levels. It is based on (or derived from)
d20 Modern (d20M). That's great for proponents of d20M, but I also bought & sold that game in the past for similar reasons. My brain is too full of d20 D&D stuff to get into unnecessarily (for me) complicated alternate d20 rules sets. So, GT's use of the d20M classes, etc. was just too much for me. For example, there seemed to be a lot of new class abilities and feats. Plus new combat rules, magic rules, etc. If it adds too much for me to willingly undertake, then I know my players would never choose it over other gaming & nongaming options available to them to spend their leisure time.
Here's a short, polite aside on
Savage Worlds (SW):
It's only 139 pages. I figure it's about 1/10 of the core d20 D&D books (PHB, DMG & MM). I sure found the information easy to process, based on having played
Deadlands and d20 (and other games to a lesser extent). I think you would find it very easy to master.
Another polite aside:
I envy your possession of the new
Warhammer Fantasy Roleplay. I investigated several reviews of it and gave it to a friend (who is an earstwhile player and DM) for his birthday. I hoped it would break him out of the D&D-only mindset. Sadly, I doubt he'll ever read it, much less expand his thinking to run it for us. Perhaps I'll pick it up someday.
Here's a longer, polite answer:
I got GT after
Slavelords of Cydonia (SOC). Both are great products, just not what I sought. I looked at SOC as a possible
Omega World (OW) campaign, but it promised to be more work than reward. SOC is billed as a product for advanced GMs. While I certainly consider myself one, I'm not willing to put that much work into my play. My buddies are pretty much mired in D&D-style play. They're getting better and more open, but I have learned that I need to minimize my investment as much as possible when I GM. I don't think GT is beyond their abilites either, but it is probably similarly beyond their willingness to play.
OW is probably as much as I want to take on in a d20 game at present. It really is a brilliant mini-game. It's a steal at $10 for a back issue of Dungeon #94. Jonathon Tweet presents an entire tool box for a new & interesting d20 game in about 40 pages. And, it's based on the classic
Gamma World. I ran a great mini-campaign of it using the
Alternity Gamma World adventures in the back of that book. Very fun. I'm even pondering how I may run The Age of Worms from Dungeon using OW. The elimination of magic has got to make the game easier to run, primarily because all the bad guys can be streamlined (SW style). Fortunately, OW characters remain fun for the players to play since they have mutations, which are essentially psionic powers instead of magic. The genius of OW is that it uses existing d20 rules for this stuff instead of entirely new machanics. The new material that is added is concise. At only 40 pages, it has to be short & sweet. That's why I love it. Here's a link for anyone who may want to pick up OW:
http://paizo.com/dungeon/products/issues/2002/94
Otherwise,
Judge Dredd (JD) is the only other d20 game I've really got my eye on possibly running at this time. I've got a couple of printed moduels that I would like to finish. JD is another derivative game that uses existing mechanics as much as possible to present a new game in a new genre. Even so, I wouldn't run it now if it weren't for the adventures I have on the shelf.
If I were to run a new D&D d20 game, I would make many changes to try to simplify the game for me to DM.
* I would probably start the PCs in generic classes from
Unearthed Arcana (UA). The feats available to generic classes in UA would allow the PCs to have just about any class abilities the players usually seek. The generic classes seem to add less magic but more feats, which is perfect for my evolving style of play since I want magic to be rare (especially magic items). Stripping the foes in pre-made adventures of most spells and magic items should make it much easier to run the game for me. I would not use the UA multiclassing suggestions for generic classes. Humans would have the ability to multiclass as per the PHB, but other races would be more restricted because there would be no favored classes available. I don't use prestige classes, so no further complications there.
*I might give any spellcaster access to the magic item creation feats at requisite levels but just make those items arbitrarily difficult to make. Fantastic components would probably figure in that equation rather than just money. Figuring what may be made from a fallen creature could become a neat use of the Spellcraft skill.
*I may use the alternate magic components rules from UA for alternate spellcasting focus requirements. It feels more magical that way.
*I would use the playing-card based initiative system of SW. It lessens the importance of the Dex bonus, but Dex reamins important enough anyway. Improved Initiative gets an extra card to choose from, so the feat remains useful.
*I would try to use the HARP criticals tables for all damage. On a successful hit, the attacker would roll d% + weapon damge as usual - 20%. That would preserve the d20 mechanics as much as possible but yield the wildly descriptive and potentially lethal HARP results. Combat should be more rare and deadly. Significantly, I would quit tracking the HPs of each & every bad guy and just eliminate the minions if the damage result is bad enough to incapacitate or kill them. PCs & significant foes would have damage tracked as HP reduction to make it more dramatic.
Sorry to get off topic there, but it shows why I made the suggestions I have made.
).
None of them are perfect, some are great for a certain personality or so.
