The game is meant to be developed for portable tablets, specifically the Android.

Oh, so you are a masochist. I see.

1. Taps and Swipes:

Game mechanics, such as movement, attacks, etc would all be handled through tapping and swiping the screen.

2. DPad + Buttons:

Movement and actions would be performed using a DPad icon in the lower left corner, and 2-4 buttons on the lower right corner.

I choose #3: Both, as selected by the user from the options menu. Seriously, if you can’t decide, just do both and let the user decide. They are both easy to implement, especially since you are using Unity 3D, so just do them both.

The second opinion I am interested in is for overall gameplay.
1. Turn Based:

The user would be able to move around the level freely, until combat begins, at which time combat would go into a turn based mode. The enemies would have a turn to move and attack, then the user would have a turn to move and attack. Initiative would be random.

2. Real Time Action:

The user would be able to move freely around the level, combat would be handled in real time. Basically, the user would enter a room and start hacking and slashing.

Once again this is easily solved by letting the player decide. Even Chrono Trigger for the Super Famicom (oh and that lesser-known Super Nintendo Entertainment System thing) had such an option, so it should be fairly standard by today’s standards.

But if I had to choose just one I would go with turn-based.
Frankly I am rather enjoying the battle system in Valkyrie Profile: Covenant of the Plume (the first and only game I have played made by my own company!) right now which is turn-based.
Who attacks first is not stupid random uninspired crap, but rather a predictable “the one who starts the fight attacks first”.

1. The more things that are random the worse your design is. Predictability means potential strategy.
2. For mobile platforms, unfortunately including Android, it is virtually required that it be turn-based, as these gamers are usually on-the-go while playing. Speaking from experience with Valkyrie Profile: Covenant of the Plume (Nintendo 3DS), I often have to stop the game to get on or off the train. Welcome to the land of mobiles—that is how it is. Mobile gamers don’t have the time to get involved in a real-time system that may make them miss their train stop or crash into another car (which they deserve to do if they are gaming and driving, but the other car doesn’t deserve it so I have to paint the picture in negative light).

Turn-based systems are like chocolate cake: Brown Delicious Fun Good.

L. Spiro

Fixed pads are horrible. For one, they don't scale well most of the time. And secondly, they don't work like people seem to imagine them working in their heads. There is no tactile feedback, and when you use a real d-pad you thumb is always touching it. You have to press it to actually get it to do something.

When it's on a screen you have to move your thumb away from the screen and then back again. You tend to miss. Or forget to lift your thumb up. And the bezel around the actual screen varies between devices. It's almost not there on a cell phone, but it's an inch or more on large tablets, making it very hard to actually get your thumb in there in the first place. On screen d-pads fail in every possible way.

You should look to Final Fantasy 3 for good dungeon crawler controls. You move with a onscreen joystick that is relative to wherever your thumb is. If you are standing next to something that can be interacted with, like a NPC or a chest, then tapping the screen anywhere will use it. Once in battle, it's menu based.

Works flawlessly.

And as L.Spiro said, it will quicksave when I need to shut it down.

I've played games that use random swipes, like that gladiator one, and they are complete trash. Yes it's a new idea, but not every idea is a good one.

You can also look at Cardinal Quest for more real time controls, but it functions like a Rogue-like.

There is also a difference between 'real-time' and 'real-time' where things get out of control fast and button mashing results (which will be impacted by less than ergonomic controls).

I havent played around with enough Mobiles to see if differences in the interfaces/system response make controls irregular so that reflex type games are impacted.

I was looking at some smartphones at a store today (I have this idea that someday they will have mini-games to connect players with MMORPs so they can do something constructive while off/away from their gaming machines)

Half the screen (top) reserved for the display (growing resolution on more models) and upto half (lower) for controls of about 3 rows of 5 columns of sufficiently large touch control buttons (big enough to have readable names on the buttons).

Now you can do alot with that many buttons even without alot of menu mutation. I would expect alot of different games (and switching between them) so there would be the need for common control placement and ease of seeing/using non standard (game dependant) button activations.

The 3D capabilities will be increasing but may take a while on the cheaper systems you may want to inclusively target. So 2D (2.5D) games will probably still be called for a long time yet You can do alot with them (as was done long ago)

One advantage of the MMORPG linked game is that a less than exciting smartphone mini-game can get a real payoff in the main MMORPG game thus keeping the players interest. A tie-in with assets in the MMORPG that determine the scenarios played and a campaign-like environment where continuous upgrades keep the game slowly changing.