First off, thanks to Kuffeh for his efforts at building a series of viewpoints.
So let's address his questions one by one. First up, what has 8th done to my army?
It is no secret that my favorite units, without regard to edition, are Knights, powerful Wizards, and Dragons.
In 7th edition, I typically loaded up on Knights, took a scroll caddy and called it good. No matter how many points I spent on magic, my opponent could easily counteract it with a scroll caddy or, in some cases, a 50 point magic item.
I seldom took a dragon because it was too strong. Even the most basic tactical ability allowed a dragon to break huge units simply by attacking from the right direction, killing everything it touched, and thus wiping out huge units with little or no risk to itself.
So two of my three favorite things to use were seldom seen (though I occasionally broke them out, and always was disappointed.)
By contrast, core quickly became "take a unit of Marauder Horsemen for each core spot requirement and call it good." The fact that everyone had access to faster moving troops that could easily wipe out my front ranks, thus allowing no attack back, could ignore or eliminate armor saves and never need come in contact with them meant that Chaos Marauders and Chaos Warriors were arguably the worst troops available to any army in the game. It was all but impossible to build a 'competitive but fun to play against" list with them.
8th has changed everything.
First off, I now plan to take a wizard every game and know I will be able to actually get some spells cast successully. That is very exciting to me and has altered the fundamental make-up of my armies.
Second, the Warhammer community in general thinks cavalry is worthless now. I happen to disagree. Where as in 7th simply wiping out the front rank usually overcame any static combat resolution, in 8th sheer killing power is valuable. So having a unit that deals out 18+ WS5 S5 attacks at I5 is pretty sweet.
And packing them 2+ ranks in means they can take some punishment and still deal out a whipping.
In 7th, the points for a second rank were wasted. In 8th, they are nearly as valuable as the front rank.
Cavalry is no longer a "rampage over everything you come across without fear of reprisal" but instead a shock troop to finish off combats.
Furthermore, infantry has a place now. A horde of marauders is now a phenomenal investment, able to withstand a couple of big hits from template weapons/spells/hard combat units and deal back some damage of their own.
Now I find myself fielding multiple units of infantry, large blocks of Knights, and a heavy dose of Wiazards...a build I enjoy playing but would never consider in 7th because frankly...it blew might chunks of hairy underarm monkey sweat.
Okay, so that answer bled into the second and third questions...but that is the beauty of 8th. In 7th, you could and often did lose games on the strategic level...simply building a list you thought might be fun was an auto-loss to anyone who put together a list that worked together.
In 8th, there is certainly a strategic level to building...but great additions to the rules such as Steadfast, Swift Reform, and removing casualties from the back rank mean the superior tactician generally is able to obtain favorable positions and when you do that, you frequently end up with victories.
I guess one other issue should be addressed. Not attacking first on the charge automatically and not being allowed to choose your weapon if you had two did make a major change to how I equip my troops.
Example: Chaos Warriors were something I routinely gave both a shield and a great weapon. Against low S, low T opponents I would use the shield. Against high T opponents...say dragons, ogres, etc., the Great Weapons made them formidable. It was very nice having a flexible troop.
In 8th, however...hand weapon and shield. Which becomes a little non-sensical since I started doing it specifically for the parry bonus since it gets very irritating having an army whose 'advantage" is its tremendous armor save only to not even get to attempt an armor save...and then giving them frenzy so they do not benefit from it anyway.
One member of our group often responds to that complaint about not getting armor saves by pointing to my respectable win-loss record...which completely misses the point. Having a toy but never being allowed to use it (and rarely being successful when you do get to use it) removes a lot of the fun.
It reminds me a bit of a wrestling-based card game I used to play. My goal in the games was to get off my "Trademark Finisher". I would rather get off my TMF and lose than not get it off and win. In fact, my all-time favorite game was one where I got off both TMFs first turn...only to lose the game to my opponent's second TMF.
It was not the win or loss that mattered...it was seeing everyone get off "their move".
In Warhammer, it is often not winning or losing but what happens along the way. I have had more success with magic in 3 games of 8 than in all of 7th combined. Ironically, it has barely impacted the games...in fact, I have taken more damage from one Skaven Plague that wiped out almost half my horde than I have dealt...but I do not care because I am getting some spells cast successfully.
By the same token, probably the most memorable 8th moment for me so far was when I threw everything I had at his H-pit Abomination...an Exalted on Juggernaut with 5 S7 attacks, a couple spells, my own H-cannon shot, my H-cannon blowing up, and finally my Shaggoth, killing it...and having it come back to life with 4 wounds, kill my Shaggoth and a nearby wizard.
Since Shaggy dies every time I put him on the table, that is expected...but it became memorable because of the secondary result.
And that, to me, is the thing...I have a relative idea of what my win-loss record was in 7th edition. In 8th, I have a better idea of the moments that were stupendously fun...my irresistable Purple Sun wounding nobody but my Wizard, the Abomination coming back, the one extra casualty that won a combat for me which in turn cost me my unit of Knights when his spell killed my BSB...taking a flank charge by hero-buffed Grail Knights and sending them off in full flight 4", but rolling a 3 for pursuit...
Those were the highlights by far.
So in conclusion to this rambling, oft off-topic bit, I have changed my army into, except for the mages, something that could be mistaken for an actual historical force of light troops, solid infantry, and shock cavalry.
It has definitely improved any troop that can deal out large numbers of quality attacks, de-emphasized "glass cannon" heroes, and brought magic back as a reliable, fun part of the game. Great job by Games Workshop.