I looked at the plug-ins available when you do a custom installation of X2, and Beatscape, Lexicon Pantheon Reverb, and Guitar Rig LE are no longer there.  Given the addition of Breverb and TH2, dropping Guitar Rig LE and the Lexicon Reverb is not particularly surprising.  However, I wouldn't have expected Beatscape to go away.

Did you look in the full manager list of plugins?
X2 makes a new list for x2 plugins, but doesn't show the whole list.

Danny

beatscape IMHO was a bad idea / waste of time compared what it should be (more akin to reasons kong or mpc type thing).. if you want something in the same vein, I'd say get fxp's geist.. in the sense of you could do far better with multiple RXP's OR the pedestrian way .. insert via browser and mess about it volume slice wise etc. also the fact of using the matrix as well.

the thing with all the stuff that uses rx2's sdk is that it is reliant on props(3rd party) updating their libs (and that didn't happen for a very long time with 64 bit)  IF there is any issue.

The Pantheon wasn't part of X1 either. Gotta agree, after using Reason that Beatscape never developed the way it should have. I like Guitar Rig LE and thankfully have both 3 & 4 to install from previous versions of SONAR.

In my opinion the Matrix view, that came in with Sonar X1 I believe, substitutes and enhances  Beatscape in the essential idea of playing together rex files coming from different collections and tempi, and being able to write a "performance" to track, out of triggering them properly.
 
If you focus on one rex loop and you want to edit it, for instance mapping slices to midi keys and playing them in a different order, or for small transpositions, then RXP is sufficient.
 
I was fond of Cyclone years ago, and later I upgraded my Sonar producer version only for Beatscape. I also moved my whole rex library to the very hidden Beatscape directory under programdata/../imported.  But frankly it was a delusion because it couldn't handle some of my favourite libs, and the capability of editing at the slice level was hidden and clunky. So finally decided to move my rexs (and Beatscape original ones) to a public place in my pc where sonar media browser can see them.
 
My idea is that Sonar is more akin to acid wav than rex. In fact my wav collection has more native tools in sonar: audiosnap+studiodrummer (or other sampler) +step sequencer, the good old loop construction view and now melodyne comes with X3..

Beatscape sounded good on paper but was not even close to what many were expecting; namely, an MPC type plug-in along the lines of FPC, Kong or groove agent.  It was buggy, unintuitive and just plain clunky.  The best part about it was the loops were decent if you are into that sort of thing. 

Here is a complete list of X2 plugins and complete list of X3 (third party included)
X2
 
Alias Factor
Analyst
2-band EQ
Boost 11 Peak Limiter
BREVERB SONAR (Producer only)
Cakewalk Sound Center
Cakewalk TTS-1
Channel Tools
Chorus
Chorus (mono)
Classic Phaser
Compressor/Gate
Cyclone
Delay
Delay/Echo (mono)
Dimension LE Synth with Garritan Pocket Orchestra (Studio only)
Dimension Pro (Producer only)
DreamStation DXi2 (32-bit only)
DropZone
DSP-FX Chorus (32-bit Only)
DSP-FX Delay (32-bit Only)
DSP-FX EQ (32-bit Only)
DSP-FX Flange (32-bit Only)
DSP-FX Studioverb (32-bit Only)
Flanger
Flanger (mono)
FX Compressor/Gate
FX Dynamics Processor
FX Expander/Gate
FX Limiter
FX2 AmpSim
FX2 TapeSim
HF Exciter
LP-64 EQ (Producer only)
LP-64 Multiband (Producer only)
MFX Arpeggiator
MFX Change Velocity
MFX Chord Analyzer
MFX Echo/Delay
MFX Event Filter
MFX Quantize
MFX Transpose
Modfilter
Multivoice Chorus/Flanger
Para-Q
Parametric EQ
Pentagon I (Producer and Studio only)
Perfect Space (32-bit Only) (Producer only)
Pitch Shifter
ProChannel (Producer only)
PSYN II (Producer and Studio only)
PX-64 Percussion Strip (Producer only)
Rapture (Producer only)
Rapture LE (Studio only)
Reverb
Reverb (mono)
Roland GrooveSynth
RXP REX Player (Producer and Studio only)
Session Drummer 3 (Producer only)
sfz Sound Font Player
Sonitus fx: Compressor
Sonitus fx: Delay
Sonitus fx: EQ
Sonitus fx: Gate
Sonitus fx: Modulator
Sonitus fx: Multiband
Sonitus fx: Reverb
Sonitus fx: Surround
Sonitus fx: Surround Compressor
Sonitus fx: WahWah
Sonitus fx:Phase
SpectraFX
Square I
Studio Instruments Bass Guitar
Studio Instruments Drum Kit
Studio Instruments Electric Piano
Studio Instruments String Section
StudioVerb 2
Tempo Delay
TH2 Producer amp simulator (Producer only)
TH2 SONAR amp simulator (Studio and Essential only)
TL-64 Tube Leveler (Producer and Studio only)
True Pianos (x86, x64) (Producer only)
TS-64 Transient Shaper (Producer and Studio only)
VC-64 Vintage Channel (Producer only)
VX-64 Vocal Strip (Producer only)
Z3ta+ (Producer only)
 
 
AAS Lounge Lizard SONAR
AAS Strum Acoustic SONAR
Session Drummer 3
Analog Chorus CH2S
Analog Phaser APH2S
Analog TrackBox
BlueVerb RV-2080
Boost 11
BREVERB SONAR
BREVERB SONAR
Brickwall BW-2S
Cakewalk Sound Center
Cakewalk TTS-1
Channel Tools
Chorus/Flanger
Classic Phaser
Compressor CP-2S
Compressor FA770
Compressor/Gate
Console Emulator
Cyclone
DeEsser DS-2S
Dimension LE
Dimension Pro
DreamStation
DropZone
Equalizer BQ2S
Equalizer BX2S
Equalizer GEQ12
Equalizer PEQ2B
Equalizer PEQ322
Equalizer PEQ5B
Gate Expander GX622
HF Exciter
Limiter LM2S
LP-64 EQ
LP-64 Multiband Compressor
Modfilter
Oilcan Echo TLE2S
Para-Q
PC4K S-Type Bus Compressor
PC76 U-Type Compressor
Pentagon
Perfect Space Convolution Reverb
ProChannel
PSYN II
PX-64 Percussion Strip
QuadCurve EQ
Rapture
Rapture LE
Roland Groove Synth
RXP
SFZ Player
Softube Saturation Knob
Sonitus Compressor
Sonitus Delay
Sonitus Equalizer
Sonitus Gate
Sonitus Modulator
Sonitus Multiband
Sonitus Phase
Sonitus Reverb
Sonitus Surround
Sonitus Surround Compressor
Sonitus Wahwah
Square I
Stereo Imager ST2S
Studio Instruments Bass
Studio Instruments Drums
Studio Instruments Electric Piano
Studio Instruments Strings
Tape Emulator
Tempo Delay
Tempo Delay 3D
TH2 Producer
TH2 SONAR
TL-64 Tube Leveler
Tone2 Bifilter2
TruePianos Amber
TS-64 Transient Shaper
Tube Saturation
Valve Driver ADR2S
VX-64 Vocal Strip
XLN Audio Addictive Drums
Z3TA+ Classic


 
It looks like the Fx plugins are gone, along with analyst.

All of the Beatscape loops were supplied with the additional content that came with X2. You get a shed load of loops without the interface that (next to) nobody liked.

Grum.